Facility for Rare Isotope Beams

Experimental tests of fundamental symmetries using nuclei and other particles subject to the strong nuclear force have led to the discovery of parity (P) violation and the discovery of charge-parity (CP) violation. It is believed that additional sources of CP-violation may be needed to explain the apparent scarcity of antimatter in the observable universe. A particularly sensitive and unambiguous signature of both time-reversal- (T) and CP-violation would be the existence of an electric dipole moment (EDM). The current generation of EDM searches in a variety of complimentary systems have unprecedented sensitivity to physics beyond the Standard Model. My talk will focus on diamagnetic systems such as Xe-129 and Hg-199 as well as certain rare diamagnetic atoms such as Ra-225 which have pear-shaped nuclei. This uncommon nuclear structure significantly amplifies the observable effect of T, P, & CP-violation originating within the nuclear medium when compared to isotopes with nearly spherical nuclei such as Hg-199. Certain isotopes of Radium (Ra) and Protactinium (Pa) are expected to have enhanced atomic EDMs and will be produced in abundance at FRIB. I will describe the present status of the ongoing EDM search in Ra-225 as well as the prospects for next generation searches for time-reversal violation in both atomic and molecular systems in the FRIB-era.

High-energy electron cooling is being considered for several accelerator physics projects worldwide, including for the Electron Ion Collider under design at BNL. Since accelerating dc electron beams above few MeV is technologically challenging, rf-acceleration of electron bunches becomes a practical approach for high-energy applications. A world's first electron cooling of ion beams employing such rf-accelerated electron bunches was recently demonstrated at BNL using the Low Energy RHIC electron Cooler (LEReC) [1]. Many challenges associated with such an approach were successfully overcome. The cooling task becomes even more challenging when one attempts to cool ion beams in collisions, requiring careful optimization between the electron cooling process and the ion beam lifetime due to various effects, including the beam-beam interactions. In this presentation, we discuss first successful application of electron cooling technique for colliding ion beams in RHIC. [1] A.V. Fedotov et al., 'Experimental demonstration of hadron beam cooling using radio-frequency accelerated electron bunches', Phys. Rev. Letters 124, 084801 (2020) Work supported by the U.S. Department of Energy.

We calculate the structure of the hypertriton in pionless effective field theory and find a pronounced Lambda-deuteron cluster structure. This motivates our investigation of the hypertriton lifetime as a function of the Lambda separation energy in an effective field theory with Lambda and deuteron degrees of freedom. We also consider the impact of new measurements of the weak decay parameter of the Lambda. While the sensitivity of the total width to B_Lambda is small, the partial widths for decays into individual final states and the experimentally measured ratio R=Gamma_3He/(Gamma_3He+Gamma_pd) show a strong dependence. We comment on recent measurements of hypertriton properties in heavy ion collisions.

Nowadays, computationally efficient many-body methods can be used to perform first-principles calculations for atomic nuclei up to mass A~150. This progress has made it possible to confront modern two- and three-nucleon interactions from Chiral Effective Field Theory with a wealth of experimental data, and provide important guidance in their ongoing refinement. In my talk, I will focus on one such many-body approach, the In-Medium Similarity Renormalization Group (IMSRG). The IMSRG not only offers a means to directly compute certain nuclear properties, but also provides a powerful framework for designing "hybrid" methods that allow us to tackle nuclei with strong collective correlations, e.g., due to intrinsic deformation. I will present IMSRG applications to the first-principles description of (doubly) open-shell nuclei, including candidate nuclei for fundamental symmetry tests. I will also give an overview of new developments that promise to once again increase the capabilities of the IMSRG and related nuclear structure methods in the coming years.

This webinar will highlight the critical role of partnerships in support of nuclear physics research. Representatives from the Department of Energy's Office of Science for Nuclear Physics, Jefferson Lab, and Brookhaven National Laboratory will describe the range of world-class expertise, facilities, and resources available throughout the DOE National Laboratory Network, as well how advances in nuclear physics impact science and society. Looking to the future, we will also discuss the rich scientific program planned for the newly approved Electron Ion Collider (EIC), as well as hear from academic researchers advancing science through partnerships with Argonne National Laboratory, Facility for Rare Isotope Beams, Jefferson Lab, and Lawrence Berkeley National Laboratory.

Beta decay is classified as allowed (if the orbital angular momentum carried by the beta particle and neutrino is L =0), first-forbidden (L =1) and so on. The so-called forbidden transitions are hindered, but not completely suppressed. As the name suggests, the vast majority of beta decay is via allowed transitions. Nevertheless, there are regions on the nuclide chart where forbidden decays are expected to compete and even dominate. One of these is the region of heavy (A~200) neutron-rich nuclei. The decay properties of these nuclei affect the nucleosynthesis of heavy elements (A~195 abundance peak) produced in the rapid neutron capture process. Since these nuclei still cannot be produced on Earth, we have to rely on theoretical prediction. However, the calculation of first-forbidden beta decay is notoriously difficult and subject to debate. In this talk I will concentrate on recent results obtained from the beta decay of 207,208Hg, nuclei close to the doubly-magic nucleus 208Pb. 208Hg provides an optimal testing ground of the competition between allowed and first-forbidden beta decays. However it populates directly only negative parity states via first-forbidden decays. The level scheme of the single proton-hole single neutron-particle 208Tl nucleus was established, providing the first direct test of the proton-neutron residual interaction in the N > 126, Z 82 quadrant [1]. In addition, the Delta(n)=0 selection rule, where n is the number of nodes in the wave function, was tested in the beta decay of 207Hg [2]. This selection rule inhibits the decays from the N>126 neutron orbitals to Z82 proton orbitals. Therefore, it forbids the otherwise "allowed" beta decays, contributing to the possible dominance of the first-forbidden transitions. [1] R.J. Carroll et al, Phys. Rev. Lett. 125, 192501 (2020) [2] T.A. Berry et al., Phys. Lett. B 793, 271 (2020)

The BNL nuclear physics program requires polarized hadron beams in the Relativistic Heavy Ion Collider (RHIC) and Electron-Ion Collider. Frequent reversals of the beam polarization direction in a storage ring can significantly reduce the systematic errors in an experiment’s spin asymmetry measurements. At high energy colliders with Siberian snakes, a more sophisticated spin flipper constructed of nine dipole magnets, was used to flip the spin in the BNL RHIC. A special optics choice was also used to make the spin tune spread very small. The same device was used to drive coherent spin motion to measure the important quantity, spin tune. The principle and experiment results are discussed.

About half of the chemical elements heavier than iron that found in nature are produced during the rapid neutron-capture process (r process). In August 2017, the observation of the kilonova light curve, an electromagnetic transient produced by the radioactive decay of r-process nuclei synthesized during the merger of two neutron stars, marked the beginning of a new era for r-process studies where nucleosynthesis predictions can be directly confronted with astronomical observations. In order to extract information about the ejecta composition producing such light curves, accurate nuclear astrophysics simulations are required. In particular, the modeling of nuclear structure properties of neutron-rich nuclei and related sensitivity studies addressing the impact of theoretical uncertainties are crucial ingredients to properly understand the nucleosynthesis of heavy elements in the universe. In this talk, I will present some recent network calculations based on nuclear input obtained within the Density Functional Theory (DFT) framework. During the first part I will discuss the role of nuclear masses and fission properties in the production of translead nuclei and the possible implications for the electromagnetic counterparts produced during neutron star mergers. In the second part of this talk, I will introduce some recent advances regarding the large-scale DFT calculation of fission fragments distributions and the estimation of theoretical uncertainties using Bayesian machine-learning techniques.

Neutrinos transport energy, drive outflows, and determine the ratio of electrons to protons in the ejecta from neutron star mergers that enriches the surrounding universe with heavy elements. Only electron flavor neutrinos and antineutrinos modify the composition of the ejecta and thus directly affect the synthesis of heavy elements. Instabilities that cause rapid mixing of neutrino flavor are likely ubiquitous in mergers, but are poorly understood and are absent from global simulations. I will present the first (local) three-dimensional simulations of this instability using the new open-source particle-in-cell neutrino quantum kinetics code Emu. I will demonstrate that the growth phase of the instability matches theoretical predictions, describe abundances of each neutrino species after the instability saturates, and discuss the implications for nucleosynthesis in neutron star mergers.

Strangeness nuclear physics based on ab initio methods is an emerging field. In this talk, I outline the foundations to investigate the third dimension of the nuclear chart. Topics include baryon-baryon interactions from chiral EFT, their application in light hypernuclei and the quest for exotic states made of hyperons. Finally, I will address the status of three-baryon forces and outline future directions in this intriguing field.

The study of heavy and superheavy elements is important for understanding nuclear structure at the limit of stability where macroscopic and microscopic effects are delicately balanced. It is a benchmark domain for a rich variety of calculations including time-dependent Hartree-Fock (TDHF) and density functional theory (DFT). One difficulty in studying these nuclei is the low formation probability. There is limited reliability in models to predict the outcome of superheavy particle formation due to the significantly large number of degrees of freedom. The fusion-fission process is a key reaction to access heavy element formation. Experiments were performed at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University and at the Heavy Ion Accelerator Facility at Aus- tralian National University to measure fusion-fission excitation functions of two different combinations of Ca+Sm and K+Pb with varying neutron-richness. The excitation functions were measured at center-of-mass energies ranging from 1.1% to 0.9% above and below the predicted barrier heights. Measured cross sections were found to be comparable above the barrier regardless of neutron-richness. At and below the barrier, cross sections were enhanced for systems with positive Q-value neutron transfer channels. Furthermore, the experiment performed at the NSCL was the first measurement of fusion- fission cross sections using the Active-Target Time Projection Chamber. This experiment demonstrated the successful reconstruction and identification of fission tracks and established the viability of performing similar experiments in the future.

Accreting neutron stars provide a unique window onto the behavior of matter at extreme density. The X-ray burst, superburst, and crust cooling episodes that several such stars go through provide signatures of the neutron star outer layers' thermal and compositional structure, along with bulk properties of the star. Interpreting these signatures requires model-observation comparisons. Meanwhile, the astrophysics model calculation results can be sensitive to the properties of the hundreds of atomic nuclei found near the neutron star surface. I will present results of numerical experiments performed with astrophysics model calculations that help prioritize nuclear physics studies, as well as results from recent nuclear physics experiments that constrain key nuclear uncertainties. I will briefly discuss the outlook for future measurements at FRIB.

Recent multi-messenger observations of explosive astronomical events are generating exciting new challenges for nuclear physics and force a rethinking of old paradigms. In particular, advanced, space-based telescopes have provided unprecedented insight into the production of chemical elements across the Galaxy, while the detection of massive neutron stars have ruled out a variety of hypotheses regarding the nature of nuclear matter. Unfortunately, despite the wealth of observational data available, many broad and open questions relating to stellar nucleosynthesis throughout the cosmos still remain, owing to large uncertainties in the underlying nuclear physics processes that drive explosive stellar scenarios. In this regard, exceptional advances in experimental nuclear physics, over the past few years, offer an exciting means to address this issue. Specifically, the latest generation of radioactive beam facilities can now act as terrestrial laboratories for the direct reproduction of astrophysical reactions, while state-of-the-art detection systems offer the possibility to study key unstable nuclei, that govern the pathway of nucleosynthesis in explosive astronomical events. In this talk, direct and indirect methods for studying astrophysical reactions will be discussed, with a specific emphasis on innovative techniques and advanced detection systems.

Particle accelerators are large complicated time-varying systems with thousands of coupled components whose performance drifts over time. For example, the resonance frequencies of RF accelerating cavities are disturbed by vibrations and drift due to temperature changes, which also introduce arbitrary offsets in the phases of RF signals. Magnet power supplies also experience disturbances in the form of high frequency ripples. The accelerated charged particle bunches are also complex and time varying objects composed of billions of interacting particles whose dynamics are governed by nonlinear collective effects such as space charge forces and whose initial conditions at the entrance of the accelerator change over time due to effects such as plasma source fluctuations and changing quantum efficiency of photocathodes. Finally, on top of all of this uncertainty, accelerators have few non-invasive diagnostics that can provide a detailed view of their beam's 6D (x,y,z,px,py,pz) phase space in real time. Typical accelerator diagnostics provide 2D slices of the 6D phase space, usually through time consuming measurements that disrupt operations, such as physically passing wires through the beams or passing the beams through various thin slits. Some of the most advanced diagnostics are provided by transverse deflecting RF cavity systems, destructive measurements that can provide 2D (z,pz) measurements. The non-invasive diagnostics that are most commonly available are beam position monitors (BPM) which provide center of mass measurements or scaler measurements such as current and loss monitors. The complexity, uncertainty, and limited diagnostics of accelerators make quick and precise adjustments of their beams' phase space challenging. In this seminar we give an overview of some of the machine learning (ML) tools that are being applied to accelerators and discuss some recent efforts at Los Alamos National Laboratory to develop adaptive model independent feedback algorithms for virtual beam diagnostics [1], online multi-objective optimization [2], online reinforcement learning for optimal control of unknown and time-varying systems [3], and adaptive ML approaches for automatic phase space controls of time-varying beams [4]. [1] A. Scheinker and S. Gessner. "Adaptive method for electron bunch profile prediction." Physical Review Special Topics-Accelerators and Beams 18.10 (2015): 102801. https://doi.org/10.1103/PhysRevSTAB.18.102801 [2] A. Scheinker, et al. "Online multi-objective particle accelerator optimization of the AWAKE electron beam line for simultaneous emittance and orbit control." AIP Advances 10.5 (2020): 055320. https://doi.org/10.1063/5.0003423 [3] A. Scheinker and D. Scheinker. "Extremum seeking for optimal control problems with unknown time‐varying systems and unknown objective functions." International Journal of Adaptive Control and Signal Processing (2020). https://doi.org/10.1002/acs.3097 [4] A. Scheinker, et al. "Demonstration of model-independent control of the longitudinal phase space of electron beams in the linac-coherent light source with femtosecond resolution." Physical review letters 121.4 (2018): 044801. https://doi.org/10.1103/PhysRevLett.121.044801

Lattice QCD offers the promise to quantitatively connect our understanding of low-energy nuclear physics to the Standard Model of particle physics. Such a connection is important for assisting with a broad range current and planned experiments such as the search for permanent EDMs in nuclei, the search for neutrinoless double beta decay, understanding the nuclear response of nuclei to a neutrino beam and possibly, constraining the nuclear equation of state by improving our understanding of the three-nucleon and hyperon-nucleon interactions. Yet, even the calculation of the two-nucleon scattering phase shifts has proved to be extremely challenging with growing tension in the literature on whether two-nucleons, at unphysically heavy pion masses, for bound di-neutron systems. The resolution of this discrepancy is critical to provide confidence to the broader community that lattice QCD can be a reliable tool for nuclear physics. It will also inform us which of the various calculational methods being used can be relied upon to deliver the correct results, and which ones are susceptible to currently unquantified systematic uncertainties. I will describe how the two-nucleon lattice QCD calculations are performed including the various challenges we face. I will then review the two-nucleon controversy, and finally, I will present progress we are making to resolve the issue.

Many fundamental questions of nuclear physics (where is the neutron dripline? where and how does the r-process occur?) hinge on how nuclear behavior changes as a function of asymmetry. Neutron elastic and inelastic scattering measurements on stable targets help constrain reaction-model asymmetry-dependence by providing information complementary to that from facilities like FRIB. This seminar will detail our recent campaign of isotopically-resolved neutron total cross section measurements on 16,18O, 58,64Ni, 112,124Sn at the Los Alamos Neutron Science Center (LANSCE) and our implementation of the Dispersive Optical Model (DOM), which connects these experimental cross sections to nuclear structure. From our DOM analysis, we make predictions for the neutron skin thicknesses of several cornerstone nuclei, then identify some major hurdles for the next generation of optical models needed to navigate the FRIB era.

Stellar formation of carbon occurs when three alpha particles fuse and form the 7.654 MeV 0+ state in 12C, the so-called Hoyle state. The Hoyle state is located above the 3a threshold, which makes the triple alpha process very unlikely as the excited carbon nucleus decays back to three alpha particles ~99.96% of the time. The remaining 0.04% will lead the formation of stable carbon. The process is therefore a bottleneck in nuclear astrophysics, and the knowledge of the production rate is imperative for accurate modelling of carbon formation in the universe. The internal decay of the Hoyle state occurs either by a 7.654 MeV E0 transition directly to the 0+ ground state, or by a 3.215 MeV E2 transition to the first-excited 2+ state. The current value of the radiative width, Grad, has been determined in an indirect way, resulting in a ~12.5% uncertainty on the 3a rate. Here we report on two experiments to improve our knowledge on Grad. The Hoyle state was excited with proton bombardment of natural carbon. In the first experiment [1], carried out at the Oslo Cyclotron Laboratory. Using the CACTUS and SiRi arrays, the 3.215 and 4.439 MeV gamma-rays were observed in coincidence with protons. The Grad / G ratio was determined from the ratio of singles proton events to number of proton-g-g triple coincidences. The new value of Grad/G is about 50% larger than the currently adopted value [3]. The second experiment [2], using the ANU Super-e spectrometer [3], the GE0/G ratio was determined from the 7.654 MeV E0 and 4.439 MeV E2 pair conversion ratios. From our measurements the recommended value of GE0/G has increased by 11% and the uncertainty has been reduced to ~5% [3]. The combined effect of the two measurements is a 34% increase in the triple-a reaction rate [1,4]. In this talk details of the experiments and the implications of the new rates will be discussed. [1] T. Kibèdi, et al., Phys. Rev. Lett. 125, 1(2020) 82701 [2] T.K. Eriksen, et al., Phys. Rec. C 102 (2020) 024320 [3] M. Freer, H.O.U. Fynbo, Prog. Part. Nucl. Phys. 78 (2014) 1 [4] https://phys.org/news/2020-10-carbon-creation-astrophysics.html * Project supported by the Australian Research Council - DP140102986 and DP170101673

Atomic nuclei, at the limits of stability, often reveal surprising phenomena such as exotic shapes and structures, unexpected level ordering and mixing and even rare modes of radioactive decay. Since the most exotic nuclei are not found naturally on earth, and have extremely short half-lives, studying them in the laboratory poses a significant experimental challenge requiring powerful rare-isotope production and accelerator facilities coupled to high-luminosity detection systems. In this talk, I will focus on radioactivity of rare isotopes and what we can learn by observing their decay products using examples from experiments performed at TRIUMF in Canada and at GANIL in France. An introduction to a novel gas-filled detection system called the Active Target and Time Projection Chamber as well as a new project, the Regina Cube for Multiple Particles, will be described in detail.

This presentation will review the fundamentals of superconducting accelerator magnet design, including material properties, magnetic, mechanical and quench protection analysis. Two specific applications will be discussed in some detail: IR quadrupoles for HL-LHC, and magnets for ECR ion sources. Broader applications of high field magnet technology will also be mentioned in areas ranging from NMR/MRI, radiation therapy and fusion energy devices.

Quantum computers hold the promise to open a new era in simulating quantum many-body systems. This era will bring us to a deeper and more complete understanding of dynamics and responses of strongly interacting systems, such as atomic nuclei, and their interactions with other forms of matter. However, current digital/universal quantum computers are too noisy and imprecise to execute the formal algorithms that have been proposed to enact such simulations. Instead, hybrid digital-analog quantum computation, where the discrete quantum processor primitives

The neutron is one of the most important constituents of matter. It is absolutely crucial for the existence of atoms heavier than hydrogen. Surprisingly, the precise value of the free neutron lifetime is still an open question, with two types of experiments (bottle and beam measurements) providing substantially different answers. I will describe the recently proposed interpretation of this discrepancy as a sign of neutron decaying to dark particles, and show that phenomenologically consistent models of this type can be constructed. I will also elaborate on the theoretical developments around this idea and discuss the efforts undertaken to verify it experimentally.

As accelerators become larger and their beams require more power, efficiency becomes an important paradigm. Energy Recovery Linacs (ERLs), the use of superconducting cavities (SRF), and permanent magnets address this concern. A collaboration between Cornell University and Brookhaven National Laboratory has designed, constructed, and commissioned CBETA, the Cornell-BNL ERL Test Accelerator at Cornell University, culminating in the first 4-turn operation that recovers energy into SRF cavities. Energy Recovery Linacs decelerate a used beam to capture its energy and use it for the acceleration of new beam. CBETA is the first SRF ERL with multiple acceleration and deceleration turns. Another first is the larger energy-acceptance return loop that simultaneously transports 7 beams of different energy through a Fixed Field Alternating-gradient (FFA) lattice that is comprised of permanent magnets. Successfully establishing 4-turn energy recovery at CBETA is especially relevant in the light of the increasing importance that ERLs have obtained: ERLs are part of the hadron coolers for the EIC, they are part of the LHeC plans, they are an integral component of an FCC-ee design option, they can be drivers for low energy nuclear physics experiments, and they have been investigated as drivers for compact Compton-x-ray sources and for industrial lithography.

Abstract: Are you connected with your “self”? with others? With your past and present? In this presentation, we will explore linkages with mental well-being. There will be opportunities for discussion and questions. About the speaker: Marsha Carolan, Ph.D., LMFT, Emeritus Associate Professor, was tenure stream faculty in the Department of Human Development and Family Studies for 25 years. In her academic career, she served as an instructor, a supervisor, and as an administrator and focused on training and advising doctoral therapy students.

The talk will discuss the state-of-the-art surface treatments for SRF cavities stressing how to obtain both high Q-factor and high accelerating gradients. The physics underneath performance improvement will be discussed and correlated with material analysis results. The talk will also discuss the technology advances in correlation with LCLS-II HE and PIP-II projects.

Ab-initio calculations of nuclei have seen explosive progress in recent years, thanks to simplifications that result from "low resolution" inter-nucleon interactions with minimal high-momentum components, such as those from chiral effective field theory. The low resolution picture is advantageous for structure calculations since wave functions are dominated by low momenta and are less correlated, calculations are more amenable to perturbative treatments, and mean-field approaches give a reasonable starting point. Many of the workhorses of nuclear structure theory, such as the nuclear shell model and density functional theory approaches, are prototypical low resolution descriptions. In recent years there has been much interest in probing the short distance/high-momentum structure of nuclei using hard electron scattering, where a high resolution picture appears to be more natural. Short-range correlations (SRCs) in nuclei are usually associated with components of the nuclear wave function with momenta well above the Fermi momentum. An important question to ask is, how do we reconcile the low resolution picture that is so prevalent in nuclear structure calculations, with the high resolution picture utilized in short-range correlation studies? In this talk, I show how the application of renormalization group (RG) methods can make sense of this conflict, showing how SRC physics is manifested differently at varying resolution scales.

The neutron is one of the most important constituents of matter. It is absolutely crucial for the existence of atoms heavier than hydrogen. Surprisingly, the precise value of the free neutron lifetime is still an open question, with two types of experiments (bottle and beam measurements) providing substantially different answers. I will describe the recently proposed interpretation of this discrepancy as a sign of neutron decaying to dark particles, and show that phenomenologically consistent models of this type can be constructed. I will also elaborate on the theoretical developments around this idea and discuss the efforts undertaken to verify it experimentally.

COMMITTEE: Hendrik Schatz (chairperson), B. Alex Brown, Edward Brown, Bradley Sherrill, Kirsten Tollefson

When exotic, secondary beams are produced at the Facility for Rare Isotopes (FRIB), a majority of the primary beam will remain unused and will be stopped in a water-traversed, spinning drum of Ti64 alloy. With the dissipation of such large amounts of energy, a plethora of valuable radionuclides is formed. Exploratory research with the heavy ion beams from the NSCL (National Superconducting Cyclotron Laboratory) demonstrated the feasibility of a synergistic collection, and the process has become colloquially termed ‘isotope harvesting’. However, next to nuclear, also radiolysis reactions are induced. The thereby created molecular radiolytic products, such as hydrogen peroxide, molecular hydrogen and oxygen, exhibit sufficiently long life times to allow an accumulation. In order to ensure adequate water conditions for isotope harvesting, knowledge about the behavior of these species is vital. The formation of radiolytic H2, H2O2 and O2 was investigated during several heavy ion irradiations at the NSCL, as well as during a high intensity proton beam experiment at the Cyclotron Research Laboratory at the University of Wisconsin–Madison. Increasing discrepancies between the predicted and observed levels were recognized at elevated beam currents. To enhance the understanding of the underlying mechanism, the radiolysis reactions inside the flowing-water target during the proton irradiation were simulated with a Python code. A correlation of the predicted yields on the applied beam currents as well as on the concentrations of hydrogen peroxide, molecular hydrogen and oxygen in the supplying water became discernible. Moreover, it could be demonstrated that the hydrogen peroxide levels are determined by the steady state, established within the entire harvesting system. With increasing levels of molecular species, the current model supports the establishment of a dose rate-dependent dynamic equilibrium. An extrapolation towards FRIB conditions allows for preliminary predictions about the molecular levels in the entire target cooling water.

The tidal deformability inferred from the Gravitational Waves, which are emitted by merging neutron stars, are instrumental in determining the equation of state (EoS) of dense matter. The importance of the observed finite nuclei properties in unveiling the correlations of the tidal deformability with the key EoS parameters will be discussed. Further, it will be shown that suitably chosen experimental data on isoscalar and isovector sensitive nuclear observables complemented with the observed maximum neutron star mass can impose tighter constrains on tidal deformability.

Our talk will report on the design, assembly, and high power conditioning of the new high gradient C-band Engineering Research Facility (CERF-NM) at Los Alamos National Laboratory (LANL). At LANL we commissioned the CERF-NM that is a test stand powered by a 50 MW, 5.712 GHz Canon klystron. The test stand is capable of conditioning single cell accelerating cavities for operation at surface electric fields up to 300 MV/m. The rf field is coupled into the cavity from a WR187 waveguide through a mode launcher that converts the fundamental mode of the rectangular waveguide into the TM01 mode of the circular waveguide for coupling into the cavity. The test stand is currently fully conditioned to operate at the power of 50 MW, 100 Hz repetition rate, and rf pulse length up to 1 microsecond. The first cavity to be tested for high gradient operation will be a beta=0.5 proton accelerating cavity fabricated at SLAC. It is well known that a notable bottleneck in achieving high-gradient in RF structures is the onset of RF breakdown. While bulk mechanical properties are known to significantly affect breakdown propensity, the underlying mechanisms coupling RF fields to bulk plastic deformation in experimentally relevant thermo-electrical loading conditions remain to be identified at the atomic scale. In this talk we will also present results of large-scale molecular dynamics simulations (MD) to investigate possible modes of coupling. We consider the activation of Frank-Read (FR) sources, which leads to dislocation multiplication, under the action of bi-axial thermal stresses and surface electric-field. With a charge-equilibration formalism incorporated in a classical MD model, we show that a surface electric field acting on an either preexisting or dislocation-induced surface step, can generate a long-range resolved shear stress field inside the bulk of the sample. We investigate the feedback between step growth following dislocation emission and subsequent activations of FR sources and discuss the regimes of critical length-scales and densities of dislocations, where such a mechanism could promote RF breakdown precursors. Some interesting simulation results will be presented and discussed.

Our talk will report on the design, assembly, and high power conditioning of the new high gradient C-band Engineering Research Facility (CERF-NM) at Los Alamos National Laboratory (LANL). At LANL we commissioned the CERF-NM that is a test stand powered by a 50 MW, 5.712 GHz Canon klystron. The test stand is capable of conditioning single cell accelerating cavities for operation at surface electric fields up to 300 MV/m. The rf field is coupled into the cavity from a WR187 waveguide through a mode launcher that converts the fundamental mode of the rectangular waveguide into the TM01 mode of the circular waveguide for coupling into the cavity. The test stand is currently fully conditioned to operate at the power of 50 MW, 100 Hz repetition rate, and rf pulse length up to 1 microsecond. The first cavity to be tested for high gradient operation will be a beta=0.5 proton accelerating cavity fabricated at SLAC. It is well known that a notable bottleneck in achieving high-gradient in RF structures is the onset of RF breakdown. While bulk mechanical properties are known to significantly affect breakdown propensity, the underlying mechanisms coupling RF fields to bulk plastic deformation in experimentally relevant thermo-electrical loading conditions remain to be identified at the atomic scale. In this talk we will also present results of large-scale molecular dynamics simulations (MD) to investigate possible modes of coupling. We consider the activation of Frank-Read (FR) sources, which leads to dislocation multiplication, under the action of bi-axial thermal stresses and surface electric-field. With a charge-equilibration formalism incorporated in a classical MD model, we show that a surface electric field acting on an either preexisting or dislocation-induced surface step, can generate a long-range resolved shear stress field inside the bulk of the sample. We investigate the feedback between step growth following dislocation emission and subsequent activations of FR sources and discuss the regimes of critical length-scales and densities of dislocations, where such a mechanism could promote RF breakdown precursors. Some interesting simulation results will be presented and discussed.

The talk will start with a light review of measurements performed over the last five decades that provided data for benchmarking models of the neutron-neutron (nn) interaction used in ab-initio calculations of few-nucleon reactions and the structure of light nuclei. The intent of the review is to share some of the story about how I got interested in this problem early in my career and how it has held my attention for more than 30 years. My focus has been on measuring cross sections for nn scattering in nuclear reactions that can be interpreted using rigorous theory. I will describe our recent cross-section measurements of nn quasi-free scattering in neutron-deuteron breakup and my aspiration to measure the cross section for the nn final-state interaction in photodisintegration of tritium. * This research is supported in part by the U.S. Department of Energy, Office of Nuclear Physics, under grant no. DE-FG02-97ER41033.

Reaction rates of light nuclei at stellar energies are key inputs to reaction network calculations predicting the abundance patterns of matter in the universe but are remarkably challenging to measure experimentally. A first-principle theory of nuclear reactions combined with an efficient computational capability to calculate their cross sections may provide accurate predictions for these rates at energies that are inaccessible to experiments. Furthermore, it can assist in providing accredited nuclear data in support of a wide range of nuclear security applications. However, due to the need for highprecision predictions, it is also imperative to provide quantified estimates for calculation uncertainties. In this talk I will outline the basics of the no-core shell model with continuum first-principle approach to light-ion reactions, demonstrate its applicability in cases relevant to astrophysics and applications, and discuss currently ongoing efforts for quantifying theoretical uncertainties.

Inclusion, diversity, equity, and accountability (IDEA) are four important attributes of Berkeley Lab's organizational culture. Chief Diversity, Equity, and Inclusion Officer, Lady Idos, will explain how IDEA defines how we work together to support the Lab's mission of "bringing science solutions to the world." Lady will share the strategic framework and initiatives for IDEA, the Lab's approach to operationalizing IDEA within talent and business processes, and the integration of psychological safety as a critical component of Team Science.

Supernova 1987A (SN 1987A) provides a unique opportunity to unravel the evolution of core-collapse supernovae (CCSNe) from the explosions to their supernova remnants (SNRs) thanks to its proximity and youth. Early observation of iron lines has indicated matter mixing during the explosion to convey innermost 56Ni to outer layers. Since the density structure of the progenitor star affects the matter mixing, it provides a hint on the properties of the progenitor star. In the meanwhile, continuous observations in X-ray bands have provided clues to understand the evolution at early SNR phases. We perform three-dimensional (3D) hydrodynamical/magnetohydrodynamical simulations of aspherical CCSNe from the onset of the explosion to an early SNR phase. The impacts of the progenitor models and parameterized aspherical explosions are investigated. The progenitor models include ones based on both the single star and binary merger scenarios. Among the models, a model with an asymmetric jetlike explosion of a binary merger progenitor, which has an advantage in explaining the features of the progenitor star and the triple-ring nebula around SN 1987A, best reproduces the observations of SN 1987A (iron lines and X-ray light curves). From the best model, the directions of the strongest explosion and the neutron star (NS) kick velocity are predicted. Recent observations of SN 1987A by ALMA have shown 3D spatial distributions of two diatomic molecules, CO and SiO, in the ejecta for the first time. Subsequent ALMA observations have also revealed a hotspot in dust emission from the ejecta, which has been interpreted as an evidence of the (undetected) NS. Our attempts to unveil the chemical evolution of the ejecta with molecule formation calculations and the properties of the NS with X-ray analyses are also presented briefly.

We report on two different accelerator technologies being developed at LBNL. First, we will describe the Neutralized Drift Compression Experiment-II (NDCX-II) at Berkeley Lab. NDCX-II is a 1 MeV induction LINAC delivering high peak ion current ([approximately] 1 A) of ultrashort pulse length (a few ns FWHM) with a beam spot of 1 mm radius on target. We will discuss its design, control system, and recent experiments. NDCX-II has been in operation for several years. The hot-plate surface lithium ion source has been replaced with a plasma source that can generate proton and helium ions in a large area ([approximately] 6 cm in diameter). Recently, NDCX-II has been used to study radiation effects induced by ions with high fluences and high dose rate in diodes and transistors. Second, we will discuss the development of a multi-beamlet, compact RF accelerator that is fabricated using a stack of inexpensive PCBoard wafers. This is a new implementation of an accelerator design from the 1980’s, but with an order of magnitude reduction in size. We have demonstrated working implementations of the basic components (focusing and acceleration elements) and recently achieved beam energies of 50 keV. The technology can be scaled up to higher currents and MeV beam energies.

YQIS provides a venue for young researchers (graduate students, post-doctoral researchers, etc.) to share their research and strengthen ties to the quantum information community. YQIS welcomes submissions from all areas of theoretical and experimental quantum information science including: Quantum algorithms, especially for simulating physics. Quantum error correction and fault tolerance. Near-term ("NISQ") algorithms and error mitigation. Quantum Shannon theory. Quantum computing technologies (superconducting qubits, photonics, etc.) Quantum resource theories. Quantum foundations. The quantum information community stands out for its cross-disciplinary nature, bringing together physicists, mathematicians, computer scientists, engineers, and more. YQIS 2021 seeks to provide a platform for early-career researchers to engage in rich, multi-disciplinary discussions and network with future leaders of the field.

EMMA is a recently commissioned recoil mass spectrometer designed for nuclear structure and astrophysics experiments with radioactive ion beams accelerated by TRIUMF's ISAC-II facility. I will describe the commissioning of the spectrometer and its first scientific experiments.

NICER, the Neutron Star Interior Composition Explorer, is an X-ray telescope that was installed on the International Space Station in 2017. Its mission is to study the nature of the densest matter in the Universe, found in the cores of neutron stars, by measuring their masses and radii. NICER uses Pulse Profile Modeling, a technique that exploits relativistic effects on X-rays emitted from the hot magnetic polar caps of millisecond pulsars. The technique also lets us map the hot emitting regions, which form as magnetospheric particles slam into the stellar surface. I will present NICER's current results and ongoing analysis and discuss the implications for our understanding of ultradense matter, pulsar emission, and stellar magnetic fields.

The recently approved multi-user upgrade of the ATLAS facility at Argonne will enable simultaneous acceleration and delivery of two different ion beams to different experimental areas. In the initial phase, one stable, nearly continuous-wave beam from the ECR ion source, and one pulsed radioactive beam from the EBIS charge breeder of the Californium Rare Isotope Beam Upgrade (CARIBU-EBIS) will be interleaved in time via a pulsed electrostatic deflector at injection, and accelerated through the first two sections of the linac. At that point, one of the beams is deflected via a pulsed switching magnet to a lower energy experimental area while the other is further accelerated through the third linac stage of ATLAS and delivered to a higher energy experimental area. Details of the proposed implementation and the expected gains from this upgrade will be presented. In addition to enhancing the ATLAS nuclear physics program, this upgrade will also increase the availability of beam time for applications such as material irradiation, isotope production R&D, and radiobiology studies with ion beams. A brief overview and typical results from these applications will be presented.

When scientists report uncertainties, what do they tell us? How excited should we get when a 3 or 4 sigma result suggests new physics? Researchers in fields from Medicine to Physics do a pretty good job of estimating the chance of small errors, but the frequency of big disagreements for even the best-made measurements is orders of magnitude greater than naively expected. Unknown problems appear to have power-law distributions consistent with how complex systems fail and how systematic errors are constrained. Occasional outliers are unavoidable at the research frontier.

Committee: Jaideep Singh (chairperson), Morten Hjorth-Jensen, Kei Minamisono, David Morrissey, Johannes Pollanen. Thesis is available at https://pa.msu.edu/academics/graduate-program/current-graduate-students/draft-dissertations-for-review/ - Select student name

When a heavy atomic nucleus fissions, the resulting fragments are observed to emerge spinning; this phenomenon has been an outstanding mystery in nuclear physics for over 40 years. The internal generation of around 6-7 units of angular momentum in each fragment is particularly puzzling for systems which start with zero, or almost zero, spin. There are currently no experimental observations which enable decisive discrimination between the many competing theories for the angular momentum generation mechanism. Nevertheless, the present consensus is that excitation of collective vibrational modes generate the intrinsic spin before the nucleus splits (pre-scission). We present comprehensive and unique new data on fission fragment spins from gamma-ray spectroscopy experiments carried out at the ALTO facility of IJC lab in Orsay on three fissioning systems 232Th(n,f), 238U(n,f), and 252Cf(SF). The v-ball gamma-ray spectrometer was coupled to the LICORNE neutron source to perform precision spectroscopy of fast-neutron-induced fission in an experimental campaign that lasted 7 weeks. The experimental results presented will be used to draw important conclusions on the intrinsic spin generation mechanism in nuclear fission. This new information is not only important for the fundamental understanding and theoretical description of fission, but also has consequences for the y-ray heating problem in nuclear reactors, for the study of the structure of neutron-rich isotopes, and for the synthesis and stability of super-heavy elements.

Type 1A supernovae (SNIa) are giant stellar explosions that have been used to make the Noble Prize-winning discovery of the acceleration of the universe. SNIa are thought to involve white dwarf stars but it is unclear how they explode. We propose a new mechanism involving a natural nuclear fission explosion. White dwarfs cool and eventually crystalize. The very first solids to form are expected to be uranium rich and may be unstable to a fission chain reaction. This physics parallels that in terrestrial nuclear weapons and we review related developments during the Manhattan Project.

Committee: Peter Ostroumov (Chairperson), Phillip Duxbury, Steven Lidia, Steven Lund, Kenji Saito. Thesis is available at https://pa.msu.edu/academics/graduate-program/current-graduate-students/draft-dissertations-for-review/ - Select student name

The large imbalance in the neutron and proton densities in very neutron rich systems increases the nuclear symmetry energy so that it governs many aspects of neutron stars and their mergers. Extracting the density dependence of the symmetry energy therefore constitutes an important scientific objective. Most current analyses have been limited to extracting values for the symmetry energy, S0, and its "first derivative" or slope L, at saturation density, 0 ~ 0.16 fm-3, resulting in constraints that appear contradictory. In this talk, I'll present an approach that can convert the S0, vs L constraints to a detailed picture of the density dependence of the symmetry energy from 0.25 to 1.5 0. The resulting symmetry energy density functional will be discussed in view of the recent Pb skin measurement from PREX and astrophysical results from LIGO and NICER.

Unlike any other physical system the nucleus represents a unique dual quantum many-body system. Its constituents, protons and neutrons, are assumed to be identical, except for their electric charge. They can be seen as two representations of the nucleon, with isospin components t_z = ±1/2 for neutrons and protons, respectively. Under the assumption of charge independence of the strong interaction, hence invariance under rotation in the isospin space, the excitation energy spectra of mirror nuclei should be identical. Isospin breaking effects, besides the dominating electromagnetic force, are usually studied through mirror energy differences, testing the charge symmetry and triplet energy differences, testing the charge independence of the nuclear force. However, a more rigorous way to test isospin symmetry are electromagnetic matrix elements. In this talk, I will present the results of our study of the A = 70, T = 1 triplet performed at the Radioactive Isotope Beam Factory at the RIKEN Nishina Center in Japan. Proton-rich beams were produced by projectile fragmentation and identified using the BigRIPS separator. Coulomb excitation was induced by a secondary Au target, located in the center of the DALI2 gamma-ray detector array to measure the excitation probabilities. The measurement on krypton-70 revealed a much larger cross section for the excitation of the first 2+ state than would be expected from its mirror selenium-70. This can be interpreted as an unexpected shape change in the mirror nuclei and the new results present a challenge to the theoretical modeling of atomic nuclei.

Neutron induced reactions play a key role in producing the chemical elements in our cosmos. About half of the abundances of elements heavier than iron are formed during quiescent burning phases in stars in the so-called slow neutron capture process, a sequence of radiative neutron captures and beta-decays. Abundances produced in this process depend sensitively on neutron reaction cross sections. After briefly introducing stellar nucleosynthesis, I will present recent neutron cross section measurements of astrophysical interest. I will focus on experiments performed at the neutron time-of-flight facility n_TOF at CERN, and how these measurements can help to understand nucleosynthesis processes in stars.

Nuclear astrophysics attempts to answer a question humans have asked for millennia: "what are we made of, and where did that stuff come from?". Today we are closer to the answering this question than ever before - we know that almost all the elements that make up our world were made in a stellar environment through nuclear reactions. Still, we do not always understand the complex web of nuclear reactions that drive the stellar processes which synthesize the elements. We can learn more about these processes and the stellar environments in which these they can occur by studying key nuclear reactions. Single- or multi-nucleon transfer reactions offer a powerful and well-understood tool for probing the nuclear reactions important to nucleosynthesis and have been used for this purpose for decades. However, there are experimental challenges inherent in these techniques: for instance, many studies employ targets with a carbon matrix, leading to fusion-evaporation residues that can be significant. Additionally, radioactive ion beam (RIB) studies are often limited by the beam rate, necessitating thicker targets to maintain luminosity, which leads to kinematic broadening in the target, decreasing the achievable energy resolution. These effects can be mitigated by measuring y rays in coincidence with particles. Gamma-ray detectors, especially those made of High-Purity Germanium (HPGe), offer dramatically better energy resolution than is achievable with the popularly used silicon particle detectors. Additionally, measurements of y rays can provide information about states not directly populated in the reaction studied and can be used to determine the lifetimes of excited states and the character of transitions between them, information which is useful for nuclear astrophysics. Particle-y coincidence studies also allow the indirect constraint of the properties of otherwise unmeasurable nuclear reactions. Many of the processes that drive stellar nucleosynthesis do so through neutron-induced reactions on radioactive nuclei. However, it is often difficult (or impossible) to directly measure these important reactions; these experiments are only feasible when the half-life of the target is greater than about 100 days. Because of the importance of these neutron-induced reactions, several indirect techniques have been developed to constrain them, including the Surrogate Reaction Method (SRM). The SRM uses an experimentally-tractable reaction and particle-y coincidence measurements to constrain the properties of the (impossible to measure) neutron-induced reaction. In this presentation, I will share recent results from Surrogate and particle-y coincidence measurements and exciting prospects for future measurements at FRIB and elsewhere. This work was supported in part by the U.S. Department of Energy National Nuclear Security Administration under Lawrence Livermore National Laboratory Contract No. DE-AC52- 07NA27344.

The cosmos is filled with billions of stars. A continuous circle of birth and sometimes cataclysmic death has continued since the beginning of our Universe. How long a star lives and how brightly it shines (how much energy is produced) by the nuclear reactions in its core. Nuclear reactions enabled by the mass, thermodynamics, and available seed material in the interior of a star define the energy and element production as well as the ultimate fate of the star. Nuclear reactions enabled by individual stellar environments also provide and define new observational signatures. Neutrino production yields direct information about the metallicity of a star or the neutron production drives the synthesis of heavier nuclei by numerous neutron induced nucleosynthesis processes whose signatures are visible in the spectra of the oldest stars as well as in the miniscule condensates that characterize meteoritic inclusions. At the University of Notre Dame's Nuclear Science Laboratory (NSL), we are engaged in exploring various aspects of reactions and subsequent decays from the very first generation stars to the spectacular mergers of neutron stars and the origins of the heaviest elements. We are developing and using the tools and techniques necessary to glimpse inside the cosmic processes. The use of high intensity stable as well as radioactive beams have been optimized for studying nucleosynthesis in a broad portfolio of stellar scenarios. I will present some of the new technical developments we have made in instrumentation and the associated physics questions. Emphasis will be placed on open questions answered and remaining. One example includes the r-process and whether the synthesis included the actinides and/or superheavies. The Nuclear Science Laboratory at the University of Notre Dame is funded by the National Science Foundation under contract Number PHY-2011890.

The Neutron-Unbound Systems Around the Dripline Topic: Prospects for future studies of neutron-unbound systems and correlations in multi-neutron decays around the dripline Studies of near-dripline, neutron-unbound systems (ND-NUS) provide important insights that help develop our descriptions of atomic nuclei. This workshop will provide opportunities to review recent investigations and discuss future work in this exciting field. Session Topics Nuclear structure and the continuum Measurements and interpretations of 2n emission The tetraneutron and many-body decays Advances in detector systems

Heavy-ion storage rings connected to radioactive beam facilities offer a unique environment for nuclear physics experiments. The Experimental Storage Ring (ESR) at GSI Darmstadt was the first of its kind and is now in operation since more than 30 years. Many novel techniques have been developed and ground-breaking measurements been performed at the ESR, for example the first experimental measurement of the bound-state beta-decay of fully-stripped 163Dy(66+) (M. Jung et al., Phys. Rev. Lett. 69, 2164 (1992)) and the first direct measurement of a capture reaction in a storage ring close to the astrophysical Gamow window (B. Mei et al., Phys. Rev. C92, 035803 (2015)). So far, storage rings have been only coupled to in-flight fragmentation facilities, for example the ESR and the CRYRING at GSI Darmstadt/Germany, the CSRe at HIRF in Lanzhou/ China, and the Rare RI Ring at RIKEN Nishina Center in Japan. A proposal to dismantle the "old" Test Storage Ring (TSR) and ship it from Heidelberg to Geneva and couple it to the ISOLDE facility was supported by the community with great enthusiasm (M. Grieser et al., Eur. Phys. J. Spec. Topics 207, 1 (2012)). Unfortunately, this project was deferred until further notice by CERN Management. Neutron capture reactions play a crucial role for the understanding of the synthesis of elements heavier than iron in stars and stellar explosions via the slow (s), intermediate (i), and rapid (r) neutron capture processes. Whereas the majority of the s-process neutron captures occur on stable or long-lived nuclei and have been experimentally constrained in the past decades, measuring the direct neutron capture cross section of short-lived nuclides (half-life [much less than] 1 year) has been so far out of reach and led to large uncertainties in Hauser-Feshbach predictions of very neutron-rich nuclei. To circumvent this problem partially, indirect measurements via (d,p) reactions in inverse kinematics are carried out, and the neutron capture cross section extracted with the help of theoretical models. Recently, a new method to couple a neutron-producing "facility" to a RIB storage ring was proposed (Reifarth and Litvinov, Phys. Rev. Spec. Topics- Acc. and Beams 17, 014701 (2014)). While their initial proposal involved a storage ring running through a high flux reactor, later ideas involved a spallation neutron source. Our storage ring project at TRIUMF proposes to use instead a compact neutron generator. The whole facility would fit into the existing ISAC experimental hall and could be operational by the end of the decade. I will introduce the TRISR project and outline some measurements that would become possible, especially with the availability of clean, intense radioisotope beams from the new ARIEL facility.

The fact that the universe is made entirely out of matter, and contains no free anti-matter, has no physical explanation. The unknown process that created matter in the universe must violate a number of fundamental symmetries, including those that forbid the existence of certain electromagnetic moments of fundamental particles whose signatures are amplified by the large internal fields in polar molecules. We discuss spectroscopic and theoretical investigations into polyatomic molecules that uniquely combine multiple desirable features for precision measurement, such as high polarizability through symmetry-lowering mechanical motions, novel electronic and bonding structures, laser cooling, and exotic nuclei.

Committee: Witold Nazarewicz (Chairperson), Metin Aktulga, Paul Gueye, Filomena Nunes, Johannes Pollanen

Committee: B. Alex Brown (Chairperson), Heiko Hergert, Carlo Piermarocchi, Kirsten Tollefson, Christopher Wrede. Thesis is available at https://pa.msu.edu/academics/graduate-program/current-graduate-students/draft-dissertations-for-review/ - Select student name

Alpha emitting radionuclides with medically relevant half-lives are interesting for treatment of tumors and other diseases because they deposit large amounts of energy close to the location of the radioisotope. Researchers at the Cyclotron Institute at Texas A&M University are developing a program to produce 211At, an alpha emitter with a 7.2 h half-life. The properties of 211At make it a great candidate for targeted alpha therapy for cancer due to its short half-life and decay mechanism. Astatine-211 has now been produced multiple times and novel chemistry has been developed for the separation of the At from the Bi target. Innovations to improve the safety and reliability of this process have been enacted.

Scattering theory is a framework connecting seemingly different phenomena of the quantum world such as stable bound states, resonances, elastic scattering, and reactions. It has applications in many areas of physics, ranging from hadrons and nuclear physics to the description of ultracold atomic systems. In particular, scattering theory provides the foundation for few- and many-body approaches that solve quantum problems from first principles, and it is an essential ingredient for the description of low-energy nuclear reactions that will be studied at the Facility for Rare Isotope Beams (FRIB).

The PREX-2 collaboration has measured the parity-violating electroweak asymmetry in the elastic scattering of longitudinally polarized electrons from the lead-208 nucleus. This long-sought measurement determines the nuclear weak form-factor at the measurement kinematics. The result provides important constraints on the neutron skin in Pb-208 and on the density dependence of the symmetry energy in neutron-rich nuclear matter near saturation density. The interpretation of the result is precise and model independent, with a small and well-estimated theoretical uncertainty. An overview of the experimental technique and results will be presented.

Committee: Peter Ostroumov (Chairperson), Paul Gueye, Yue Hao, Steven Lund, Kendall Mahn.

Committee: Alexandra Gade (Chairperson), Daniel Bazin, B. Alex Brown, Sean Liddick, Kirsten Tollefson. Thesis is available at https://pa.msu.edu/academics/graduate-program/current-graduate-students/draft-dissertations-for-review/ - Select student name

The equation of state (EoS) of dense matter is an essential ingredient in astrophysical models, e.g., in the study of neutron-star properties and the simulation of core-collapse supernovae or neutron-star mergers. The chemical composition of matter is of particular interest and the description of many-body correlations is a challenge in global EoS models. A generalized relativistic density functional predicts the formation of light nuclear clusters at sub saturation densities [1]. Such low-density matter can be found also at the surface of heavy nuclei. Cluster correlations can modify their surface eproperties, e.g., the thickness of the neutron skin [2]. The formation of alpha particles at the surface of tin nuclei (mass numbers 112 - 124) was studied experimentally with knockout reactions using a proton beam at RCNP, Osaka [3]. The isotopic dependence of the reaction cross section shows a good agreement with the theoretical prediction. In this seminar, the generalized density functional, the results of the alpha knockout experiment and future strategies will be discussed.[1] S. Typel et al., Phys. Rev. C 81, 015803 (2010)[2] S. Typel, Phys. Rev. C 89, 064321 (2014)[3] J. Tanaka et al., Science 371, 260-264 (2021).

Committee: Yue Hao (Chairperson), Daniel Hayden, Steven Lidia, Steven Lund, Filomena Nunes

High power, pulsed proton rings rely on charge exchange injection to control the phase space density while the charge density of the beam is increased. Traditional charge exchange injection from an H-linac into a ring relies on very thin carbon foils to strip the electrons from the hydride. The presence of the foil material in the path of the beam introduces complications such as scattering of beam resulting in high radiation in the vicinity of injection. Additionally, while foil technology has advanced considerably over the decades with latest foils able to sustain megawatt beam cycles for months, there is still a fundamental beam power density limitation on the foils. Next generation machines will need to rely on alternative methods for charge exchange. One such method under development is the laser assisted charge exchange method (LACE), which utilizes magnets and lasers in place of the foil to remove the electrons. This talk will discuss the successes and limitations of foil technology, and the development of the LACE technique as a candidate for replacing the foils in future high power accelerators.

State-of-the-art gamma beam facilities such as HIyS at Duke University and ELI-NP in Romania, along with emerging detector technologies, are permitting key advances nuclear structure and astrophysics. Here, I present two examples; elucidating the structure of the Hoyle state in carbon-12 and measuring the cross section for the 12C(a,y)16O reaction using an optical TPC detector at HIyS. The carbon/oxygen ratio at the end of stellar helium burning is a hugely important nuclear input to stellar evolution calculations. However, it is not known accurately, due to significant uncertainties in the 12C(a,y)16O cross section. In our new study [1], angular distributions of the 12C(a,y)16O reaction were obtained by measuring the inverse 16O(y,a)12C reaction with gamma-beams and a Time Projection Chamber (TPC) detector. Data for the total reaction cross section and angular distributions from Ecm = 2 - 3.3 MeV are presented. Secondly, the structure of carbon-12 was explored by populating the 2+ excitation of the Hoyle state at 10 MeV using gamma beams [2]. An optical TPC detector allowed separation of decays through the 8Be ground state and those through excited states in 8Be, or indeed, direct decays. By placing an upper limit on the direct decay branching ratio (BR) of this 2+ state, a theoretical extrapolation permitted the direct decay BR for the Hoyle state to be determined. [1] R. Smith, M. Gai, et al. "Precision measurements on oxygen formation in stellar helium burning with gamma-ray beams and a Time Projection Chamber." Preprint, Research Square, (2021). [2] R. Smith, M. Gai, et al. "Stringent upper limit on the direct 3a decay of the Hoyle state in C 12." Physical Review C 101, 021302 (2020).

The SAMURAI spectrometer at RIKEN became operational in 2012, with the commissioning and Day1 campaign. Later campaigns have seen this complex setup extended with additional arrays, such as the MINOS active target for high luminosity experiments or the NeuLAND demonstrator for the detection of more than two neutrons. We will review some examples of the exotic physics that have been addressed during this period, going from the search for Efimov states in Boron isotopes to the quest for multineutron systems.

Superconducting proton linacs can be used as a driver for a wide range of applications including spallation neutron source, accelerator driven nuclear energy production, neutrino physics study, and medical application. However, the construction and operation of such a superconducting proton linac is expensive. In this talk, we will discuss a new type of proton linac, recirculating superconducting proton linac, and its recent advances. This accelerator has the potential to substantially reduce the cost of a superconducting proton linac by using much less number of superconducting cavities.

From the speaker: "What do knots have to do with quantum mechanics? What do elementary particles have to do with quantum computers? In this talk, I will discuss an exciting approach to developing a quantum computer based on dragging elementary particles around each other to form knots. While this may sound rather bizarre, substantial steps towards this goal have already been achieved." Presenter Steven H. Simon has been a theoretical physics professor at Oxford University since 2009. From 2000 to 2008, he was the director of theoretical physics research at Bell Laboratories. He is known for his work on topological phases of matter, topological quantum computing, and the fractional quantum Hall effect. He is also the author of a popular introductory book on solid-state physics-"guaranteed to be the funniest book on solid-state physics you will ever read."

The Interstellar Medium (ISM) is continuously fed with new nucleosynthetic products. The solar system moves through the ISM and collects interstellar dust particles that contain such signatures including the radionuclides iron-60 (t1/2=2.6 Myr) and plutonium-244 (81 Myr); both can be measured with Accelerator Mass Spectrometry (AMS) with high sensitivity. AMS measurements demonstrate indeed a global iron-60 influx and is evidence for exposure of Earth to recent (10 Myr) supernova explosions. Recent detection of ISM-plutonium-244 in deep-sea archives complements the positive detection of interstellar and supernova-produced iron-60. In contrast to iron-60, plutonium-244 is exclusively produced by the r process. Presence of plutonium-244 in the ISM can thus place strong constraints on r-process frequency and production yields over the last few 100 Myr. The low concentrations of plutonium-244 measured in deep-sea archives suggest a low abundance of interstellar Pu and supports the hypothesis that the dominant actinide r-process nucleosynthesis is rare. Here I will report on the first time detection of a quantitative influx of the r-process nuclide plutonium-244 onto Earth and link this to a concomitant-possibly frequent-influx of supernova-iron-60. These new data combine supernovae and r process signatures in the ISM for the last 11 Myr

SPIRAL2 is the new high-intensity linear accelerator, part of the GANIL facility. This 200kW facility can accelerate light ions to heavy ions at energies up to 40 MeV/u and 14.5 MeV/u, respectively. After its construction in 2014 and in parallel with the installation of the superconducting linac (SC), the validation of the sources, the low energy lines and the RFQ was carried out. Commissioning of the SPIRAL2 linac began as soon as the French Nuclear Safety Authority authorisation was obtained on 8 July 2019. The settings of the MEBT, linac and high-energy lines (HEBT) to the beam dump and to the Neutron For Science (NFS) experiment room were validated during the two six-month commissioning periods. Stable operation with a 16 kW proton beam (10% of the nominal beam power) has been achieved, showing that the conditions are already met (beam loss control) to be able to operate at maximal power (160 kW proton, 200 kW deuteron). The various commissioning stages and the results obtained are presented.

Attaining high quantum yield, low emittance, and long lifetime from an alkali antimonide photocathode has remained a sustained focus in recent years, due especially to the need for electron beams of high average current for strong hadron cooling. The ongoing development of photocathodes is motivated by the unprecedented needs of this application, namely simultaneous optimization among photoemission metrics that tend to be linked by the underlying physics. The challenge of optimizing these processes and their linked photoemission metrics has driven improvements in cathode material characterization and new fabrication techniques. At BNL, a new suite of materials science tools is now available to address the poor crystallinity and lack of surface and bulk engineering that has previously limited the performance of these materials. In situ and real time x-ray characterization study has been performed to reveal the compositional, structural and surface evolution of the alkali-based photocathodes prepared using different growth techniques and recipes, as well as their correlation with quantum efficiency and degradation mechanisms. The structural, stoichiometric and surface information revealed by these measurements are essential for optimizing the cathode quantum efficiency, emittance and operational lifetime for applications in future light sources.

Axion-like particles (ALPs) are hypothetical pseudo-Nambu-Goldstone bosons which are a candidate of dark matter. Since they couple with photons, ALPs can be produced in hot astrophysical plasma. Once produced, ALPs decay into photons which may be observable with gamma-ray telescopes. I calculated the ALP emission from a thermonuclear (i.e. type Ia) supernova and a massive star in the final stage of stellar evolution. It is shown that gamma-rays that originate from ALPs can be a target of next-generation gamma-ray telescopes and provide an independent constraint on ALP parameters. Also, ALPs may affect energy transfer in core-collapse supernovae. I will mention a preliminary result on supernova explosion aided by heavy ALPs.

From the speaker: "Lightning strikes our planet about a billion times per year, killing as many people as hurricanes or tornadoes. Surprisingly, despite its familiarity, we still don't understand many things about lightning, including how it gets started inside thunderstorms and how it travels such large distances through air. In addition, many new and strange phenomena have been discovered in and around thunderstorms, including colossal jellyfish-like structures near the edge of space called sprites, enormous, expanding rings of light called elves, bizarre, bluish jets shooting out of cloud tops, powerful flashes of gamma rays emanating from deep inside storms, and large but nearly-invisible discharges called dark lightning. In this presentation, I will talk about the mysteries of lightning and other weird things that lightning does."

The Spallation Neutron Source (SNS) has been in operation for neutron science since 2006 at the Oak Ridge National Laboratory. The SNS provides the most intense, pulsed accelerator-based neutron beams in the world. It uses 1.4 MW of average proton beam power on its liquid mercury target to generate neutrons for research. Most of the proton beam energy is imparted by the superconducting linac portion of the accelerator. In its early years of operation, the superconducting accelerating cavities suffered from excessive parasitic electron activity leading to thermal instability and reduced accelerating gradients. As the result, the proton beam energy remained at 940 MeV, below the SNS design beam energy of 1000 MeV. To remediate this issue, a new in-situ processing technique was proposed and developed. The technique centered on using a plasma inside the resonant cavities to further process their inner RF surfaces and allow increased accelerating gradients. The presentation will cover the successful development and deployment of this new technique leading to a proton beam energy of 1 GeV for neutron production.

Matrix quantum mechanics plays various important roles in theoretical physics, such as a holographic description of quantum black holes. Understanding quantum black holes and the role of entanglement in a holographic setup is of paramount importance for the development of better quantum algorithms (quantum error correction codes) and for the realization of a quantum theory of gravity. Quantum computing and deep learning offer us potentially useful approaches to study the dynamics of matrix quantum mechanics. For this reason, I will discuss a first benchmark of such techniques to simple models of matrix quantum mechanics. First, I will introduce a hybrid quantum-classical algorithm in a truncated Hilbert space suitable for finding the ground state of matrix models on NISQ-era devices. Then, I will discuss a deep learning approach to study the wave function of matrix quantum mechanics, even in a supersymmetric case, using a neural network representation of quantum states. Results for the ground state energy will be compared to traditional Lattice Monte Carlo simulations of the Euclidean path integral as a benchmark.

The bottom row of the periodic table is famous for its radioactive elements, which compared to stable isotopes are very little-explored. Many of these heavy radioisotopes have exotic nuclei which grant them enhanced discovery potential. Radioactive elements also hold promise for advancing technology. Modern atomic physics techniques, such as laser cooling and trapping, allow for efficient use of unstable elements and their study in highly-controlled environments. We will discuss our recent work with laser-cooled radium ions. This ion provides new opportunities for optical clocks. It is also promising for controlling other radioactive atoms and molecules at the level of single quantum states and studying them with high precision spectroscopy. We will also discuss recent work with trapped radioactive molecules and their prospects for studying time symmetry violation to address open questions in physics.

Committee: Artemis Spyrou (Chairperson), Kaitlin Cook, Claudio Kopper, Heiko Hergert, Sean Liddick

Two of the overarching questions animating the International Research Network for Nuclear Astrophysics (IReNA) are: “How did the Universe create the chemical elements we are made of?” and “What do stars tell us about the building blocks of matter?” Neutron stars are cosmic laboratories uniquely poised to answer these two fundamental questions. The historical detection of gravitational waves from the binary neutron star merger GW170817 by the LIGO-Virgo collaboration is providing fundamental new insights into the astrophysical site for the creation of the heaviest elements in the cosmos. In turn, electromagnetic observations of neutron stars are placing stringent constraints on the nature of dense, neutron-rich matter through the precise determination of stellar masses and radii. Finally, the study of exotic nuclei at terrestrial facilities will help elucidate the structure, dynamics, and composition of neutron stars. It is the strong synergy between heaven and earth that will be the focus of this presentation.

Two of the overarching questions animating the International Research Network for Nuclear Astrophysics (IReNA) are: “How did the Universe create the chemical elements we are made of?” and “What do stars tell us about the building blocks of matter?” Neutron stars are cosmic laboratories uniquely poised to answer these two fundamental questions. The historical detection of gravitational waves from the binary neutron star merger GW170817 by the LIGO-Virgo collaboration is providing fundamental new insights into the astrophysical site for the creation of the heaviest elements in the cosmos. In turn, electromagnetic observations of neutron stars are placing stringent constraints on the nature of dense, neutron-rich matter through the precise determination of stellar masses and radii. Finally, the study of exotic nuclei at terrestrial facilities will help elucidate the structure, dynamics, and composition of neutron stars. It is the strong synergy between heaven and earth that will be the focus of this presentation.

Since the first definitive measurements of the Quark Gluon Plasma using heavy-ion collisions nearly 20 years ago, the field has made significant progress in understanding its dynamical description using relativistic viscous hydrodynamics. Due to constraints from 100's of experimental data points, it is now possible to make precise predictions about how the Quark Gluon Plasma flows. With this level of precision, it has opened up entirely new questions that can be probed within the field of heavy-ion collisions. For instance, it has been discovered that heavy-ion collisions are sensitive to nuclear deformations that affect an observable known as elliptical flow. This has been confirmed in 129Xe where a quadrupole deformation was needed to reproduce experimental data. This then opens the door to looking for other intriguing possibilities such as alpha clustering in 16O. Furthermore, since the Quark Gluon Plasma is relativistic, far-from-equilibrium, and extremely tiny, we have a better understanding of the connection between the limitation on the smallest droplet of a fluid and causality. Looking to the future, we will discuss consequences of the far-from-equilibrium nature of the Quark Gluon Plasma at large baryon densities when one searches for the Quantum Chromodynamics critical point.

An overview of underling physics in high-energy or/and high-power particle beam interactions with matter in accelerator applications and its implementation in the Monte Carlo simulations is presented and discussed. Effects in materials under irradiation, materials response related to component lifetime and performance are considered with a focus on existing and future accelerator complex needs. The implementation of this multi-faceted physics and adequate state-of-the-art computing techniques in the modern Monte Carlo codes, code main features, results of the code benchmarking, validation, and intercomparison are described.

Committee: Dean Lee (Chairperson), Alexei Bazavov Heiko Hergert, Matthew Hirn, Saul Beceiro Novo, Filomena Nunes

Committee: Peter Ostroumov (Chairperson), Sergey Baryshev, Yue Hao, Kirsten Tollefson, Remco Zegers

The CREX and PREX experiments at Jefferson Laboratory use parity violating electron scattering to determine neutron densities. The PREX measurement for 208Pb constrains the density dependence of the symmetry energy and the pressure of neutron rich matter. This has important implications for neutron stars. The CREX measurement for 48Ca provides a test of microscopic chiral effective field theory calculations and the importance of three neutron forces. In addition, these measurements can aid in the interpretation of atomic parity and coherent neutrino scattering experiments. We describe the CREX experiment, present the remarkably accurate results, and compare to earlier PREX results.

Committee: Paul Gueye (Chairperson), Marcos Caballero, Paul DeYoung, Kendall Mahn, Witold Nazarewicz, Remco Zegers

The density of states is a fundamental property of nuclear structure that plays an important role in nuclear reactions, especially radiative capture, which determines elemental abundance from nucleosynthesis. Historically, it has been difficult to obtain a reliable estimate the density of states from nuclear structure models. Consequently, empirical models have been used with parameters constrained by data from nearby nuclei. However, this practice is prone to severe error as small errors in the parameters are amplified by the exponential growth in the density of states. Here, the density of states is estimated making use of the nuclear shell model, which is designed to accurately describe the low-lying structure of atomic nuclei. Naturally, even in the shell model it is not computationally viable to enumerate each and every state. Instead, we propose to exploit properties of the principal tool used in the shell model, Lanczos diagonalization, to find a statistical estimate of the density of states within the shell model configurations. It will be shown that with a judicious choice of the starting vector, it is possible to accurately compute moments of the Hamiltonian (up to the eight moments, and in principle higher), which will then permit the Lanczos matrix to be modeled and extrapolated to any iteration number. It will be shown that this extrapolated Lanczos matrix yields a spectrum very similar to that of the exact shell model. Applications to iron and germanium isotopes will be shown. In addition, extensions of the method to compute transition strength functions will be discussed.

One of the major issues in modern astrophysics concerns the analysis of the present composition of the Universe and its various constituting objects. The composition of the various constituents of the Universe at the galactic and stellar scales has evolved since the Big Bang. The study of this evolution has been the subject of an enormous amount of observational, experimental and theoretical work. Nucleosynthesis models aim to explain the origin of the different nuclei observed in nature by identifying the possible processes able to synthesize them.

A key open question in the field of nuclear astrophysics relates to the production of heavy elements throughout our Galaxy. In particular, the origins of 35 n-deficient nuclides in between Se and Hg, that cannot be formed by neutron capture processes remain obscure. At present the production sites for p-nuclei are believed to be Type-II supernova, however a lack of experimental information on reaction rates makes any comparison with astrophysical observations extremely difficult. Sensitivity studies have been performed to identify reactions which significantly affect the production of p-nuclei, one of which is 83Rb(p,y)84Sr. Due to the energies involved in the p-process and the need for an intense beam 83Rb of there is no prior experimental information on this reaction rate, or indeed any p-process rate involving a radioactive reactant. In this talk I will discuss the first direct measurement of a p-process reaction rate involving a radioactive beam, 83Rb(p,y)84Sr. This pioneering measurement was performed at the TRIUMF ISAC-II facility with the newly commissioned recoil mass spectrometer EMMA in conjunction with the segmented HPGe array TIGRESS. I will detail the efforts and integrating the two spectrometers, including the upgrade of the TIGRESS DAQ, as well as detail the results from this measurement.

The abstraction of musical structures (notes, melodies, chords, harmonic or rhythmic progressions, etc.) as mathematical objects in a geometrical space is one of the great accomplishments of contemporary music theory. Building on this foundation, I generalize the concept of musical spaces as networks, and derive functional principles of compositional design by the direct analysis of the network topology. This approach provides a novel framework for the analysis and quantification of similarity of musical objects and structures, and suggests a way to relate such measures to the human perception of different musical entities. Finally, the analysis of a single work or a corpus of compositions as complex networks provides alternative ways of interpreting the compositional process of a composer by quantifying emergent behaviors with well-established statistical mechanics techniques. In particular, I will demonstrate how tonal harmony, or any other compositional framework, emerges naturally as a property of the network topology.

Plunger devices are used worldwide to measure the lifetime of excited nuclear states on the order of hundreds of femto- to picoseconds. Deduced transition probabilities are used to test and refine nuclear models. These are more sensitive to the nuclear wavefunction than the excitation energy of the corresponding states. I will briefly give an idea on the method using the Doppler shift of gamma decays to determine lifetimes. If the time allows the newly established charge-plunger technique will be covered in the talk as well. Specific constrains using plunger devices, different setups and the analysis will be discussed. A new device is built and can be combined to 4pi charged particle detector arrays for experiments as Atlas and later with reaccelerated beams at FRIB. A short discussion about user support during a pandemic and which tools were used for successful experiments at Argonne is included

Committee: Hironori Iwasaki (Chairperson), Alexandra Gade, Sean Liddick, Filomena Nunes, Pengpeng Zhang. Thesis is available at https://pa.msu.edu/academics/graduate-program/current-graduate-students/draft-dissertations-for-review/ - Select student name

One- and two-proton radioactivity are the latest radioactivities discovered. Although predicted as early as 1960, it took more than 20 years to observed the first ground-state one-proton radioactivity and more than 20 additional years to discover two-proton radioactivity. Both decay modes can be used to study nuclear structure beyond the limits of nuclear binding. I will first describe the evolution of nuclear decay modes when moving from stability to the proton drip line. Then the discovery of 2p radioactivity will be shortly reviewed and new results be presented. Next a new detector, ACTAR TPC, will be introduced. This detector has been used recently to study the decays of the high-lying high-spin isomers 54Nim and 53Com and the results from these measurements will be presented.

The Fermilab Accelerator Science Facility (FAST), is a research machine to conduct accelerator proof-of-principle experiments as well as technology development to enable future particle physics accelerator facilities. The centerpiece of the facility is the Integrable Optics Test Accelerator (IOTA), a small storage ring designed to satisfy the requirements of a diverse beam physics research program using either electron or proton beams. This talk will discuss some of the challenges of accelerator physics and how the IOTA/FAST experimental program addresses them. The covered topics include nonlinear beam dynamics, beam instabilities, beam cooling, and photon science.

The equation of state (EoS) of QCD is a crucial input for the modeling of heavy-ion-collision (HIC) and neutron-star-merger systems. Calculations of the fundamental theory of QCD, which could yield the true EoS, are hindered by the infamous Fermi sign problem which only allows direct simulations at zero or imaginary baryonic chemical potential. As a direct consequence, the current coverage of the QCD phase diagram by lattice simulations is limited. I will discuss two different equations of state based on first-principle lattice QCD (LQCD) calculations [1, 2]. The first is solely informed by the fundamental theory by utilizing all available diagonal and non-diagonal susceptibilities up to 𝒪(μ4) in order to reconstruct a full EoS at finite baryon number, electric charge and strangeness chemical potentials. For the second, we go beyond information from the lattice in order to explore the conjectured phase structure, not yet determined by LQCD methods, to assist the experimental HIC community in their search for the critical point. We incorporate critical behavior into this EoS by relying on the principle of universality classes, of which QCD belongs to the 3D Ising Model. This allows one to study the effects of a singularity on the thermodynamical quantities that make up the equation of state used for hydrodynamical simulations of HICs. Additionally, we ensure that these EoSs are valid for applications to HICs by enforcing conditions of strangeness neutrality and fixed charge-to-baryon-number ratio. I will show the features of and quantities produced by these EoSs and compare them. [1] J. Noronha-Hostler, P. Parotto, C. Ratti, J.M. Stafford, Physical Review C 2019, 100, 064910 [2] J.M. Karthein, D. Mroczek et al, Eur.Phys.J.Plus 136 2021 6, 621

The neutron time-of-flight facility, nToF, has been operating at CERN since 2001. It is based on a pulsed neutron source coupled to two different flight paths (namely EAR1-185 m long, set horizontally with respect to the beam axis and EAR2-20 m long, set vertically), designed to study neutron-nucleus interactions for neutron energies ranging from a few meV to several GeV. The wide energy range and high-intensity neutron beams produced at nToF are used to make precise measurements of neutron-related processes. A new experimental facility, the so-called NEAR station, set really close to the spallation target and especially tuned for nuclear astrophysics and radiation damage studies, is currently under commissioning. Neutron time-of-flight measurements contribute in an important way to the understanding of stellar evolution and supernovae, while intense neutron beams are also important in studies of how to incinerate radioactive nuclear waste. The current presentation is an overview of all the recent research activities of the nuclear physics group of NTUA at nToF related to these fields.

Many of the discoveries of the vastly varying properties of nuclei were and continue to be made using “reaction probing” between a beam and target nucleus. Because many interesting nuclei are rare and nowadays produced as radioactive beams, clever experimental techniques have to be devised to push the limits of our exploration. I will illustrate this quest via two experimental methods that provide high luminosities, in-beam gamma-ray spectroscopy using high velocity knockout reactions, and lower energy reactions in inverse kinematics performed in active targets. The future extended reach of radioactive beams at FRIB and other facilities, combined with complementary and efficient experimental methods to explore the properties of nuclei via reaction probes, will push forward our knowledge in nuclear science.

Committee: Bradley Sherrill (Chairperson), Kaitlin Cook, Peter Ostroumov, Carlo Piermarocchi, Oleg Tarasov

Type I X-ray bursts on the surface of accreting neutron stars are the most frequently observed thermonuclear explosions in the universe. Understanding these explosions and the systems that produce them gives us insight into fundamental physics such as the dense equation of state, nuclear reactions we cannot replicate on Earth, and the influence of strong magnetic and gravitational fields. In this talk I will present a multi-dimensional time-dependent implicit model of the heating, ignition and burning of accreted fuel that powers such X-ray bursts on the surface of accreting neutron stars. The software I present will be publicly available shortly. I will present the first science results modelling the effect that a hotspot on the surface of the neutron star, caused by the channeling of the accreted fuel, has on the ignition location of X-ray bursts.

Type I X-ray bursts on the surface of accreting neutron stars are the most frequently observed thermonuclear explosions in the universe. Understanding these explosions and the systems that produce them gives us insight into fundamental physics such as the dense equation of state, nuclear reactions we cannot replicate on Earth, and the influence of strong magnetic and gravitational fields. In this talk I will present a multi-dimensional time-dependent implicit model of the heating, ignition and burning of accreted fuel that powers such X-ray bursts on the surface of accreting neutron stars. The software I present will be publicly available shortly. I will present the first science results modelling the effect that a hotspot on the surface of the neutron star, caused by the channeling of the accreted fuel, has on the ignition location of X-ray bursts.

Type I X-ray bursts on the surface of accreting neutron stars are the most frequently observed thermonuclear explosions in the universe. Understanding these explosions and the systems that produce them gives us insight into fundamental physics such as the dense equation of state, nuclear reactions we cannot replicate on Earth, and the influence of strong magnetic and gravitational fields. In this talk, I will present a multi-dimensional time-dependent implicit model of the heating, ignition and burning of accreted fuel that powers such X-ray bursts on the surface of accreting neutron stars. The software I present will be publicly available shortly. I will present the first science results modeling the effect that a hotspot on the surface of the neutron star, caused by the channeling of the accreted fuel, has on the ignition location of X-ray bursts.

Committee: Georg Bollen (Chairperson), Oscar Naviliat-Cuncic, Witold Nazarewicz, Chong-Yu Ruan, Hendrick Schatz. Thesis is available at https://pa.msu.edu/academics/graduate-program/current-graduate-students/draft-dissertations-for-review/ - Select student name

We report on the development of machine learning models for classifying C100 superconducting radiofrequency (SRF) cavity faults in the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab. Of the 418 SRF cavities in CEBAF, 96 are designed with a digital low-level rf system configured such that a cavity fault triggers recordings of rf signals for each of the eight cavities in the cryomodule. Subject matter experts analyze the collected time-series data and identify which of the eight cavities faulted first and classify the type of fault. This information is used to find trends and strategically deploy mitigations to problematic cryomodules. However, manually labeling the data is laborious and time consuming. By leveraging machine learning, near real-time-rather than postmortem-identification of the offending cavity and classification of the fault type has been implemented. We discuss performance of the machine learning models during a recent physics run. We also discuss efforts for further insights into fault types through unsupervised learning techniques, and present preliminary work on cavity and fault prediction using data collected prior to a failure event.

From the speaker: "Supermassive black holes are millions to billions of times the mass of the Sun and reside in the centers of most galaxies (including our own Milky Way). When two galaxies collide, the effects on their central supermassive black holes can be dramatic. Galaxy mergers funnel gas towards their centers, where it creates spectacularly bright fireworks as it spirals into the black holes. Eventually the two black holes form a close binary pair, emitting powerful gravitational waves as they spiral toward each other and merge to form one larger black hole. Gravitational waves-ripples in the fabric of spacetime-were first detected by the Laser Interferometer Gravitational-Wave Observatory in 2015, a discovery that was awarded the 2017 Nobel Prize in Physics. Now we stand on the cusp of the next frontier: detections of low-frequency gravitational waves from supermassive black hole binaries. I will describe our recent work to model supermassive black hole populations across cosmic time and make predictions for gravitational-wave sources, using large simulations of galaxy collisions and cosmological volumes."

The study of dynamic nuclear processes is at the heart of understanding physical phenomena at scales spanning the minute interactions between quantum many-body systems to the massive mergers of neutron stars. Even restricting one's view to a single reaction between two well-defined collision partners, it is clear that there exists a complex interplay between transfer, collective excitations, dissipative effects, etc. To address these disparate effects and phenomena a comparably robust microscopic approach, time-dependent density functional theory (TDDFT), has been used to study the real-time evolution of nuclear systems. I will highlight recent advances and ongoing work in low-energy nuclear dynamics by focusing on studies focusing on three separate dynamical processes: heavy-ion fusion, quasifission, and fission. By exploring these mechanisms in detail, a fuller picture of nuclear dynamics begins to emerge and the challenges in nuclear physics at the edge of stability are exemplified. Testing and expanding the limits of our theoretical understanding in this regime is more important than ever as our ability to explore exotic nuclear reactions with unstable partners is poised to expand greatly as we enter the FRIB era, further probing and eroding the terra incognita of the nuclear landscape.

Over the past few years, a series of new studies of the Standard Model (SM) corrections to the beta decay of mesons, nucleon and nuclei carried out by me and my collaborators has led to the observation of several significant anomalies in beta decays, in particular the apparent violation of the Cabibbo-Kobayashi-Maskawa (CKM) matrix unitarity. They have attracted world-wide attentions and turned beta decays into one of the most promising avenues for the search of physics beyond the Standard Model (BSM). However, the current significance level of the observed anomalies is not yet sufficient to declare a discovery, and the major limiting factor is the precision level of the SM theory inputs. In this talk I will outline a 5-year research proposal designed to systematically calculate the most important SM inputs to various beta decay processes, including the radiative corrections, isospin breaking corrections and nuclear structure corrections, to an unprecedented precision level. The success of the proposed research could increase the significance level of the existing beta decay anomalies beyond 5 standard deviations and lead to one of the earliest confirmed observations of BSM physics, of which impact to the fundamental science is far-reaching.

Ab initio methods, for which the only input is the inter-nucleon interaction, play an important role in describing nuclei for which there is limited data, particulalry in regions of the nuclear chart far from stability. However, quantitative predictions are computationally limited by the explosion in scale as the number of nulceons increases. Approximate symmetries of the nucleus can be used to combat this explosion using symmetry adapted approaches. At the same time, these symmetries can be used to gain insight into simple patterns which arise in the spectrum. I will discuss the emergences of two such approximate symmetries, SU(3) and Sp(3,R), associated with nuclear deformations, rotations and giant resonnances and how these symmetries are employed in the ab initio symplectic no-core configuration iteraction framework.

Some of the most interesting questions in modern physics are those regarding the nature, origin, and interactions of the fundamental constituents of matter. The answers to such questions can make a huge difference in how we understand the universe. Investigating them often involves an exciting combination of applications from many different fields - nuclear physics, particle physics, astrophysics, and more - to design and implement detectors capable of detecting tiny signals that could provide hints of new physics. In this talk, we describe a few of the questions our lab is trying to answer and how we look for physics beyond the standard model.

Ab-initio methods provide a direct connection between nuclear physics and the underlying fundamental theory, permitting the use of nuclei as probes to study fundamental physics. In order to do this, we need to start from a nuclear model constructed from first-principles such in chiral effective field theory. Then reliable and accurate methods to solve the Schrödinger equation are needed.
In this seminar we will introduce the Hyperspherical Harmonic (HH) method as the approach we used to solve the Schrödinger equation. We will focus in particular on some recent improvements that permit to treat nuclei up to A = 6. We will then show some examples on how this method, together with chiral effective field theory, has been used to study time reversal violation and β-decay in light nuclei. Finally we will briefly discuss how the HH method could be extended to treat also scattering states, opening up new frontiers for the ab-initio calculations.

Background: Recent developments in effective field theory and many-body theory have pushed the limits of ab initio calculation to the 208Pb region with impressive precision [1]. This means that it becomes possible to obtain first-principles computation (with quantified uncertainties) of quantities which even reside in the heavy-mass region. The quantities include these relevant for astrophysics and searches for physics beyond the Standard Model. However, ab initio calculations for scattering and reactions are much more limited. Methods: F (Facilities, ab initio many-body method, such as in-medium similarity renormalization group, IMSRG) for R (Resonance and continuum), I (astrophysics), and B (Beyond the Standard Model) Results: I will discuss how to couple nuclear scattering states and decay channels into the IMSRG framework by using the complex-energy Berggren representation. The new IMSRG approach can describe properties of weakly-bound and unbound open quantum systems, such as limits of atomic nuclei, resonance, and halo. I will also report ongoing efforts to extend IMSRG to unify nuclear structure and reactions, especially for proton or neutron scattering and radiative capture reactions. In the second part of this talk, I will introduce some unreported strong correlations between electric dipole polarizability, binding energy, and symmetry energy parameters unlocked by large scale (range from 40Ca to 132Sn) ab initio calculations. Based on these correlations, I will show robust constraints on the equation of state of nuclear matter. Last but not least, I will present the recent ab initio calculation of nuclear responses for dark matter direct detection. Conclusion: FRIB physics needs theoretical 'FRIB'. [1] Ab initio predictions link the neutron skin of 208Pb to nuclear forces. B.S. Hu, et al. In preparation (2021).

The purpose is to maintain ISNET's mission of bringing the nuclear physics and statistical sciences communities together to report on the latest progress and to provide a vehicle for educating and enlightening the nuclear physics community in regards to the application of statistical methodologies that enable nuclear physics to reach more quantitatively rigorous scientific conclusions. The dates for the meeting are December 14th - 16th 2021, and will start Tuesday morning and end Thursday afternoon. For 2021 ISNET 8 will be an "a hybrid " meeting. All talks will be delivered on-site, but sessions will also broadcasted via ZOOM for remote participants. https://indico.frib.msu.edu/event/47/

Committee: Hironori Iwasaki (Chairperson), Kaitlin Cook, Sean Liddick, Dean Lee, Stuart Tessmer

Despite considerable progresses during the last decades, the origin of trans-iron elements is not yet fully understood. These elements are thought to be produced by a variety of nucleosynthetic processes, the main ones being the so called slow (s) and rapid (r) neutron capture processes. An intermediate neutron capture process (i-process) is also thought to occur at neutron densities intermediate between the s- and r-processes. This is supported by the observation of metal-poor stars whose chemical compositions is between the s- and r-processes (the so called r/s-stars). An important challenge is to associate each nucleosynthetic process with its astrophysical source(s). In the first part of the presentation, I will discuss the synthesis of trans-iron elements in low metallicity massive stellar models. In particular, I will show how stellar rotation is expected to alter the synthesis of heavy elements both during the life and explosion of the massive star, and ultimately lead to a material with a chemical composition intermediate between the standard s- and r-processes. In the second part of this presentation, I will focus on the development of the i-process in low-metallicity AGB stars models. In both parts, I will highlight the chemical fingerprint of the discussed nucleosynthetic processes, identify key reaction rates and compare model predictions with observed r/s-stars.

Visualization of structural changes of materials with atomic spatial (Angstrom) and temporal resolutions (femtosecond) is of crucial importance to the understanding of the relation between structure and functionality, and the ultimate goal of controlling energy and matter [1]. In the past decades, ultrafast electron diffraction/microscopy (UED/UEM) has been rapidly developing, aiming to provide the relevant length and time scales for ultrafast science [2-3]. With the advent of high accelerating gradient radiofrequency photoinjector, high brightness electron beam at mega-electron-volt (MeV) energy has become accessible for UED to reach ~1 Å spatial resolution and ~100 femtosecond temporal resolution. In 2014, SLAC National Accelerator Laboratory launched a UED/UEM initiative, aiming to provide the world's leading ultrafast electron scattering instrument using MeV electron beams. A prototypical MeV UED beamline was built and has been evolving over the years [4-6] for the goal that has long been envisioned -- making space-and-time resolved molecular movies. A great number of successful ultrafast scientific results have been achieved at SLAC MeV UED in the regions of condense matter physics, warm-dense matter physics, as well as chemical science [7-9]. Since 2019, SLAC MeV UED has become an official user facility as part of Linac Coherent Light Source to serve the ultrafast science community [10]. In this talk, the experimental set up of SLAC MeV UED and selected ultrafast scientific results will be presented. Research and development efforts to further expand the capabilities of SLAC MeV UED will also be discussed. [1] "Directing matter and energy: Five challenges for science and the imagination", A Report from the Basic Energy Sciences Advisory Committee, 2007, (http://science.energy.gov/~/media/bes/pdf/reports/files/gc_rpt.pdf). [2] R. J. D. Miller, Science 343, 1108 (2014). [3] Ahmed H. Zewail, Science 328, 187 (2010). [4] S. P. Weathersby, et al., Review of Scientific Instruments 86, 073702 (2015). [5] X. Shen, et al., Ultramicroscopy 2018, 184, 172-176. [6] X. Shen, et al., Struct. Dyn. 6, 054305 (2019). [7] E. J. Sie, et al., Nature 565, 61 (2019). [8] M. Z. Mo, et al., Science 360, 1451 (2018). [9] J. Yang, et al., Science 361, 64 (2018). [10] SLAC MeV UED user facility webpage (https://lcls.slac.stanford.edu/instruments/mev-ued)