Facility for Rare Isotope Beams

A critical constraint on solar system formation is the high 26Al/27Al abundance ratio of 5e-5 at the time of formation, which was about 17times higher than the average Galactic ratio, while the 60Fe/56Fe value was about 2e-8, lower than the Galactic value of 3e-7. This challenges the assumption that a nearby supernova was responsible for the injection of these short-lived radionuclides into the early solar system. We show that this conundrum can be resolved if the Solar System was formed by triggered star formation at the edge of a Wolf-Rayet (W-R) bubble. Aluminium-26 is produced during the evolution of the massive star, released in the wind during the W-R phase, and condenses into dust grains that are seen around W-R stars. The dust grains survive passage through the reverse shock and the low density shocked wind, reach the dense shell swept-up by the bubble, detach from the decelerated wind and are injected into the shell. Some portions of this shell subsequently collapses to form the dense cores that give rise to solar-type systems. The subsequent aspherical supernova does not inject appreciable amounts of 60Fe into the proto-solar-system, thus accounting for the observed low abundance of 60Fe. We discuss the details of various processes within the model using numerical simulations, as well as nucleosynthesis modelling, and analytic and semi-analytic calculations. We conclude that it is a viable model that can explain the initial abundances of 26Al and 60Fe.

Unraveling nuclear forces in nature remains one of the active frontiers in the nuclear science research. The forces among the neutrons as well as those among nucleons and hyperons, being still largely unknown, play a role in the equation of state of neutron stars and dense matter and the structure properties of rare isotopes. On the theoretical front, only a systematic approach based on the underlying theory of strong interactions (QCD) may enable reliable predictions with quantifiable uncertainties. Effective field theories of few-nucleon forces can in principle be constrained by experiment, however, with scarce experimental data for systems involving few neutrons and the hyperons, theoretical predictions remain limited. Recent advances in computational capabilities have allowed the quantum theory of strong interactions to be solved for few-nucleon systems. Physical scattering amplitudes can be directly accessed and the missing input to effective field theories can be obtained. Although this program is still limited to unphysical inputs for the quark masses, with increased computational resources towards the Exascale, major progress in physical light nuclear systems is anticipated. In this talk, I present the results of a recent study by the NPLQCD collaboration that demonstrates the path from QCD to nuclear and hypernuclear forces. These results reveal intriguing properties of nuclear and hypernuclear forces that are consistent with the predictions of QCD in the limit of a large number of colors. Further progress in obtaining reaction and structure properties of light nuclei from QCD will be briefly reviewed.

Startups and large corporations are full of physicists, many hiding in plain sight. Why? I will discuss the strong parallels between basic research in nuclear/particle physics, founding teams at great startups, and leaders at some of the world's largest corporations. How big are these opportunities (mission and capital), and what can we do to help prepare more physicists for such roles?

We present a simple, yet previously unnoticed, polarization phenomenon involving ion beams accelerated at medium energies. In the 7Li(12C,12C)7Li(7/2-) reaction at 24 MeV/A, a large longitudinal polarization of the excited 7Li outgoing product has been observed, by measuring the angular correlations between the fragments (alpha+t) of the decay of the populated 7/2- resonance. A theoretical account of the reaction process supports the idea that we are dealing with a universal effect present under very general conditions whenever there is a transfer of angular momentum from the relative motion of the colliding nuclei to the internal degrees of freedom of the projectile. We make an attempt at unveiling the origin of this effect with a simple kinematical argument.

The response of nuclei to external probes has many applications across the field of astrophysics. A precise description of neutral and charge-exchange excitations is necessary to compute the rates of various processes such as neutron-capture, beta-decay, neutrino-scattering or electron-capture, which are needed for the modeling of nucleosynthesis and stellar evolution. In this talk I will present a theoretical approach to the description of the nuclear response. This method describes the nucleus as a system of relativistic protons and neutrons interacting via effective meson exchange, and builds inter-nucleon correlations by accounting for the coupling between single nucleons and collective vibrations of the nucleus. Such correlations typically induce fragmentation and spreading of the transition strength which are essential for a precise description of giant resonances and low-energy modes, and have a great impact on the computing of decay and reaction rates. I will present calculations of various excitation modes and corresponding astrophysical rates in mid-mass and heavy nuclei. Emphasis will be put on recent calculations of Gamow-Teller transitions for beta-decay and electron-capture rates.

COMMITTEE: Witold Nazarewicz(Chairperson),H. Metin Aktulga, S. Balasubramaniam, A. Gade H. Hergert

Quantifying uncertainties within nuclear reaction theory has become more prominent over the past several years given recent improvements in the models and quality of rare isotope data. Here, I will discuss the progress that we have made quantifying parametric uncertainties in direct, few-body reaction theory. This will focus on a comparison between frequentist and Bayesian methods in order to constrain elastic scattering cross sections as well as predict the transfer cross sections that use the same potentials.

COMMITTEE: Morten Hjorth-Jensen(Chairperson), Scott Bogner, Alexandra Gade, Carlo Piermarocchi, Scott Pratt (Thesis is on display in 1312 BPS bldg. and the NSCL Atrium)

The standard model (SM) predicts a very small value (~10-40 e cm) for the electric dipole moment of the electron, de. However, the SM fails to predict dark matter and the asymmetry between matter and antimatter in the universe. Extensions to the SM that deal with these deficiencies tend to predict a much larger de, and therefore a precise measure of de directly impacts our understanding of the matter/antimatter asymmetry and of dark matter. We propose a new method for measuring de which uses polar molecules embedded in a solid argon matrix. We refer to this method as EDM3 (Electric Dipole Measurements using Molecules in a Matrix). The method of extracting de using EDM3 will be described. Because of the long observation times available for the stationary molecules, and the large numbers of molecules that can be embedded, EDM3 shows promise for improving the measurement of de by many orders of magnitude.

The US population is made up of over 50% women. Hispanic Americans and African Americans make up over 30% of the US population. The processes by which we foster curiosity, educate our youth, encourage people into science, recruit and retain people into physics and welcome them as members of our nuclear physics community results in a much different demographic. Enabling the development of an identity as a scientist or nuclear scientist is a crucial part of mentoring young people to successful careers in nuclear science.

We discuss a new method for calculation of extremal eigenvectors and eigenvalues in systems where direct calculation is problematic. By constructing a basis out of a few, well-behaved eigenvectors, we show how more accurate results can be extracted where other methods fail. Applications to neutron matter and the Bose-Hubbard model are discussed, as well as an outlook to calculations of electromagnetic observables in carbon isotopes.

TRIUMF\'s Ion Trap for Atomic and Nuclear science (TITAN) exploits the textbook-like conditions and versatility of ion traps, which offer sophisticated manipulation of a single ion or a cloud, for beam preparation and high-precision measurements. To test the unitarity of the quarkmixing matrix, to understand stellar evolution, and to benchmark state-of-the-art predictions of the N = 32 subshell closure in titantium isotopes require mass spectrometry. On the other hand, in-trap decay spectroscopy has focused on investigations of the double beta-decay problem and is being extended to studies of electron influence on fundamental decays. A selection of recent results will be presented as well as technical developments useful at radioactive-ion-beam facilities.

COMMITTEE: Remco Zegers,(Chairperson)Norman Birge, B. Alex Brown, Sean Liddick, Michael Thoennessen

Non-relativistic quantum matter, as realized in ultracold atomic gases, continues to be a remarkably versatile playground for many-body physics. Experimentalists have exquisite control over temperature, density, coupling, and shape of the trapping potential. Additionally, a wide range of properties can be measured: from simple ones like equations of state to more involved ones like the bulk viscosity and entanglement. The latter has received much attention due to its connection to quantum phase transitions, but it has proven extremely difficult to compute: stochastic methods display exponential signal-to-noise issues of a very similar nature as those due to the infamous sign problem affecting finite-density QCD. In this talk, I will present an algorithm that solves the signal-to-noise issue for entanglement, and I will show results for strongly interacting systems in three spatial dimensions that are the first of their kind. I will also present a few recent explorations of the thermodynamics of polarized matter and other cases that usually have a sign problem, using complexified stochastic quantization.

COMMITTEE: Morten Hjorth-Jensen, Chairperson Scott Bogner Piotr Piecuch Carlo Pieromarocchi Remco Zegers Thesis is on display in 1312 BPS bldg. and the NSCL atrium

Efforts to describe nuclear structure and dynamics from first principles have made phenomenal progress in recent years. Exact methods for light nuclei are now able to include continuum degrees of freedom and treat structure and reactions on the same footing. Moreover, computationally efficient many-body methods like Coupled Cluster, Self-Consistent Greens Function theory, and the In-Medium Similarity Renormalization Group (IMSRG) are nowadays routinely applied for nuclei as heavy as the tin isotopes. These developments make it possible to confront modern nuclear interactions and electroweak operators that are rooted in Quantum Chromodynamics with a wealth of existing and forthcoming experimental data. Focusing on the IMSRG as a representative example, I will present recent results for ground- and excited state observables, and discuss their implications for many-body methods and interactions. I will then look ahead at efforts to refine the input interactions and currents, expand the capabilities for computing transitions and response functions, and develop computational tools that are necessary for a controlled description of heavy open-shell nuclei. These developments will allow us to support the experimental push towards exotic nuclei, e.g., by studying the evolution of nuclear properties from the proton to the neutron drip lines, and to contribute to major fundamental symmetry experiments like the search for neutrinoless double beta decay.

The concept of personalized medicine, where each patient is treated according to an individually tailored treatment regime, has gained much recognition over the past few years. In nuclear medicine this trend is parallelized by an increased demand for novel radionuclides, fulfilling the characteristics of a “matched pair”. This comprises the use of the same pharmaceutical, labeled either with a diagnostic or a therapeutic radionuclide. Ideally both radioisotopes should belong to the same chemical element and, in this case, the radionuclides 43Sc and 47Sc fit this requirement. The decay characteristics of 43Sc (t1/2= 3.9 h, Eβ+av = 476 keV [88%], Eγ = 372 keV [23%]) are well suited for Positron Emission Tomography imaging, while the low energy β--emitter 47Sc (t1/2= 3.4 d, Eβ-av = 162 keV, Eγ = 159 keV [68%]) could be utilized for targeted tumor therapy. In the course of this work, different production and separation methods for 43Sc and 47Sc were investigated, aiming to obtain the activity in a sufficient quality and quantity for direct radiolabeling. The feasibility of producing 43Sc via proton irradiation of two different target materials (43Ca and 46Ti) was studied so far. Two neutron induced reactions, 46Ca(n,γ)47Ca→47Sc and 47Ti(n,p)47Sc, were investigated towards the generation of 47Sc. After chemical separation and purification, the radionuclidic purity and labeling quality of the obtained nuclides were compared and the in vivo applicability demonstrated in proof-of-concept studies.

Tributyl phosphate (TBP) is an important industrial extractant used in the Plutonium Uranium Reduction Extraction (PUREX) process to recover hexavalent uranium and tetravalent plutonium from irradiated nuclear fuel. Metal extraction by TBP was traditionally considered to proceed through the formation of discrete coordination complexes. However, recent work has suggested that colloidal, self-assembled reverse micellar structures may be responsible for metal recovery under conditions of high metal and acid loading. In this work, the existence of such mesoscale structures in solution is evaluated using a combination of experimental and computational chemistry techniques. Organic phase samples containing TBP-extracted hexavalent uranium and tetravalent zirconium (a plutonium surrogate) in a nonpolar solvent were characterized using diffusion NMR spectroscopy, rheology, and small angle neutron scattering. These experiments yielded contradictory results when interpreted using models applicable to colloidal systems, suggesting that reverse micelles are not present in TBP extraction systems. TBP aggregation in classical molecular dynamics simulations of samples containing nitric acid is consistent with this conclusion, and suggest that TBP forms small, discrete species in solution.

In a particle collider the electromagnetic interaction of one beam with the other, the beam-beam effect, is typically one of the most performance limiting effects. Operational head-on beam-beam compensation was first attempted in the 1970s in the 4-beam collider DCI but failed due to the unanticipated coherent motion of the beams. In 2015 operational head-on beam-beam compensation has been implemented in the Relativistic Heavy Ion Collider (RHIC) in order to increase the luminosity delivered to the experiments. We discuss the principle of combining a lattice for resonance driving term compensation and an electron lens for tune spread compensation. We describe the electron lens technology and its operational use, and report on measurements of the lattice properties and the effect of the electron lenses on the hadron beam. We also provide an estimate of the luminosity gain.

This talk concerns several recent approaches using effective field theory (EFT) to describe nuclear system. First, on the nucleon-nucleon (NN) interaction level, to resolve the issue of the conventional chiral EFT approach (Weinberg power counting), a new power counting which is free of the renormalization group problem is introduced. Then we propose a new way to apply the EFT interaction in truncated model space to perform ab-initio calculations. Finally, recent approaches toward a systematic treatment of effective interactions within the energy density function (EDF) framework will be discussed. Results of nuclear matter up to NLO based on this approach will be presented.

COMMITTEE: Hendrik Schatz(Chairperson),Edward Brown, Alexandra Gade, Carl Schmidt,Artemis Spyrou Thesis is on display in 1312 BPS bldg. and the NSCL atrium

Everyone\'s journey is unique and filled with big and small obstacles. Dr. Renee Horton has experienced obstacles and still has succeeded in pursuing her dream. The talk, You Can Have your Dream, travels Renee’s path through failures, small success, obstacles, disappointments and finally landing in her dream job. Renee currently serves as the Metallic/Weld Engineer for NASA Space Launch System (SLS) in New Orleans, LA, which comes full circle after dreaming as a child on working for NASA as an astronaut. She may not be an astronaut, but she helps put them into space. Renee believes that if you find your intersection between your talent and your passion, you find your true happiness; this talk will highlight her dissertation studying Self Reacting Friction Stir Welding, her non-profit she founded and the overall intersectionality of her life.

A non-zero Electric Dipole Moment (EDM) in a non-degenerate system violates time-reversal (T) symmetry, and therefore charge-parity (CP) symmetry due to the CPT theorem. EDM measurements are therefore sensitive and background-free searches for new CP violating interactions. Ra-225, with its octupole deformation and nearly degenerate nuclear parity doublet, is an extremely attractive candidate for probing CP violations in the hadronic sector. Our latest measurement limits the EDM of Ra-225 to be less than 1.4x10^(-23) e-cm (95% CL), and is the first ever measurement of an EDM limit using laser cooled and trapped atoms. Further experimental upgrades are being implemented including an electric field upgrade to enhance the EDM sensitivity and STIRAP-based electron shelving for improved state detection efficiency. With these upgrades in place our EDM sensitivity should increase by about two orders of magnitude and allow us to substantially improve constraints on certain T-violating processes within the nucleus. Updates on the status of these upgrades will be provided.

The multi-years WMAP followed by Planck results tightly constrain the baryonic density in the Universe with highest precision ever achieved, resulting more constrains in the light element abundance predicted in the Standard Big Bang Nucleosynthesis (SBBN). The observed amount of all other light elements H,D,3He,4He agrees well with the SBBN calculation but the 7Li is observed 3-4 times less than calculated amount, which is referred as \'Lithium problem\'. We performed 7Be+d reaction at energies relevant to SBBN, which could destroy a fraction of the mass-7 nuclei in the condition of the Big Bang and could offer an explanation of the observed deviation from the prediction of SBBN. We investigated 7Be+d reaction at SBBN energies using a radioactive 7Be beam and deuterium gas target, stopping the beam in the target gas inside the ANASEN detector at the Florida State University. The ANASEN is an active gas target detector system which tracks the charged particles using a position sensitive proportional counter with position sensitive double sided silicon detectors all backed up by Caesium Iodide (CsI) detectors. The experiment measured a continuous excitation function by slowing down the beam in the target gas down to zero energy by using a single beam energy. Our experimental set-up provides a high detection efficiency for all relevant reaction channels focusing on the lowest energies, relevant to the BBN. Results of this experiment will also be presented along with experimental techniques.

COMMITTEE: Filomena Nunes(Chairperson),Morten Hjorth-Jensen, Witold Nazarewicz, Brian O’Shea, Artemis Spyrou

In coupled-channel models the poles of the scattering S-matrix are located on different Riemann sheets. Physical observables are affected mainly by poles closest to the physical region but sometimes shadow poles have considerable effect, too. The purpose of this paper is to show that in coupled-channel problem all poles of the S-matrix can be calculated with properly constructed complex-energy basis. The Berggren basis is used for expanding the coupled-channel solutions. The location of the poles of the S-matrix were calculated and compared with an exactly solvable coupled-channel problem: the one with the Cox potential. We show that with appropriately chosen Berggren basis poles of the S-matrix including the shadow ones can be determined.

The lepton number violating process of neutrinoless double-beta decay could result from the physics beyond the Standard Model needed to generate the neutrino masses. The MAJORANA DEMONSTRATOR is an experiment constructed to search for neutrinoless double-beta decays in germanium-76 and to demonstrate the feasibility to deploy a large-scale experiment in a phased and modular fashion. It consists of two modular arrays of natural and 76Ge-enriched germanium detectors totalling 44.1 kg, located at the 4850\' level of the Sanford Underground Research Facility in Lead, South Dakota, USA. The achieved ultra-low backgrounds and excellent energy resolution make a strong case for a tonne-scale 76Ge experiment. I will discuss the physics and design elements of the MAJORANA DEMONSTRATOR, recent results from its search for neutrinoless double-beta decay, and the plan for a future tonne-scale 76Ge experiment LEGEND.

The 14N(p, )15O reaction is the slowest stage of the carbon-nitrogen-oxygen cycle of hy-drogen burning and thus determines its reaction rate. Precise knowledge of its rate is required to improve the model of hydrogen burning in our sun. The reaction rate is a necessary ingredient for a possible solution of the solar abundance problem that led to discrepancies between predictions of the solar standard model and helioseismology. The solar 13N and 15O neutrino fluxes are used as independent observables that probe the carbon and nitrogen abundances in the solar core. This could settle the disagreement, if the 14N(p, )15O reaction rate is known with high precision. After a review of several measurements its cross section was revised downward due to a much lower contribution by one particular transition, capture to the ground state in 15O. The evaluated total relative uncertainty is still 7 %, in part due to an unsatisfactory knowledge of the excitation function over a wide energy range. The talk reports experimentally determined cross sections as astrophysical S-factor data at twelve energies between 0.357 – 1.292 MeV for the strongest transition, capture to the 6.79 MeV excited state in 15O with lower uncertainties than before and at ten energies between 0.479 – 1.202 MeV for the second strongest transition, capture to the ground state in 15O. In addition, a new R-matrix fit is presented to estimate the impact of the new data on the astrophysical relevant energy range.

Recent advances in the processing of bulk superconducting radio frequency (SRF) niobium cavities via interior surface impurity diffusion have resulted in significant improvements in their quality factor (Q0). The motivation for the development of these processes is to reduce the cryogenic operating cost of current and future accelerators while providing reliable operation. The potential for higher Q0 in SRF cavities was first realized by titanium doping during high temperature annealing of SRF cavity at 1400 [degrees Celsius] and later by nitrogen doping at 800 [degrees Celsius] followed by electropolishing (EP). However, despite the increase in Q0, the quench field of the cavities doped by titanium or nitrogen is often limited to much lower values than achieved by standard treatments. Progress has been made when the cavities are heat treated at lower temperature in order to preserve the accelerating gradient with high quality factors. In this talk, I will review the recent R&D at Jefferson Lab on SRF cavities and samples processed along the cavity in order to better understand the mechanism behind the high quality factor.

Abstract: Part II. The selection of vacuum materials and treatment will be described. The vacuum system design, engineering, implementation and operation will be demonstrated through examples, some applicable to FRIB. The first part was presented on November 16, 2017 and it is available here https://portal.frib.msu.edu/Lists/Announcements/AllItems.aspx

COMMITTEE: Hironori Iwasaki (Chairperson), B. Alex Brown, L. Chomiuk, W. Fisher, A. Gade

The strong coupling to decay/reaction channels is an essential feature of nuclei in the vicinity of the driplines and requires new theoretical developments for the study of these systems far from stability. In reaction models, one usually reduces the many-body picture to a few-body one, where only the most relevant degrees of freedom are retained. In such approaches one introduces effective interactions, the so-called optical potentials, between the clusters considered. Traditionally one uses parametrized interactions constrained by data on β-stable isotopes. The application of these phenomenological potentials to exotic regions of the nuclear chart is unreliable and it is therefore critical for progress in the field of reactions that these effective interactions be connected to the underlying microscopic theory. During this talk, I will show results towards our goal of constructing a nucleon-nucleus microscopic potential using recent chiral-EFT Hamiltonians within the Coupled Cluster approach.

Neutron-rich nuclear systems reveal particular phenomena such as shell evolution with proton-neutron asymmetry, halos and neutron skins. Large efforts are being made worldwide to reach the most neutron-rich nuclei and investigate how their structure differ from stable ones, leading to stringent tests for the predictive power of state-of-the art nuclear structure models. In this seminar, the most recent results from a three-year gamma-spectroscopy campaign at the Radioactive Isotope Beam Factory (RIBF) of RIKEN in Japan, today's most powerful accelerator to produce neutron-rich nuclei. The concept of PUMA (antiProton Unstable Matter Annihilation), a new project at CERN, will be introduced. PUMA aims at using low-energy antiprotons to probe the tail of the matter density of neutron rich nuclei. It should provide a new way to investigate the emergence of neutron skins and halos.

Unlike the conventional picture of nucleons moving independently in mean-field orbitals, experiments show that 20% of nucleons in nuclei have momentum greater than the Fermi momentum. These high-momentum nucleons are predominantly composed of evanescent short-distance neutron-proton (np) pairs interacting via the tensor force. This np-pair dominance implies that protons move faster than neutrons in neutron-rich asymmetric nuclei. In addition, these np-pairs appear very closely associated with nucleon modification in nuclei as measured by the EMC effect. This talk will discuss the evidence for these short-range correlated pairs, their connection to the EMC effect, and the possible implications for neutron stars, nucleon modification in nuclei, and neutrino oscillation measurements.

Neutrinos are elusive particles interacting weekly with the atomic nuclei and electron plasma. Most of the atomic nuclei that are stable from the strong interaction point of view can decay emitting neutrinos or antineutrinos. The properties of weak interaction are essential for the understanding of the fundamental symmetries that constrain the Standard Model of particle physics, and which represent one of the main pillars of the FRIB science. In my talk I will analyze the neutrino physics relevant for the double beta decay of the atomic nuclei, one of the main projects under investigation by the low-energy nuclear physics community.

Science, technology and innovation will play a crucial role in helping countries achieve the ambitious Sustainable Development Goals (SDGs). Since the discovery of nuclear fission in the 1930s, the peaceful applications of nuclear technology have helped many countries improve crops, fight pests, advance health, protect the environment and guarantee a stable supply of energy. Highlighting the goals related to health, hunger, energy and the environment, in this presentation I will discuss how nuclear technology contributes to the SDGs and how nuclear technology can further contribute to the well-being of people, help protect the planet and boost prosperity.

Lisa Carpenter, NSCL - "Cluster Structure and Three-Body Decay in 14C"
Abstract: Recent model calculations with most advanced methods for cluster states have shown the need of experimental data to probe the structure of light exotic nuclei, including those with α-clustering, such as 14C. The prototype Active Target Time Projection Chamber (pAT-TPC) allows us to investigate these types of structures, giving access to the full excitation function with a single beam energy. This type of experiment measures resonances in 14C that can be compared to the models. Additionally, using a Dalitz-type analysis, three-body decays can be analyzed to determine probabilities of "democratic" and "sequential" decay. The measurement was carried out by resonant alpha-scattering of a 10Be beam at 40 MeV delivered by the TwinSol facility at the University of Notre Dame. Preliminary results will be presented including event reconstruction using the Random Sample Consensus method.

Sara Ayoub, NSCL - "SECAR: The Separator for Capture Reactions in Astrophysics"
Abstract: Proton- and alpha-capture reactions on unstable proton-rich nuclei power astrophysical explosions like novae and X-ray bursts. Studying these processes is crucial to understanding the mechanisms behind those explosions and the nucleosynthesis at those sites. The Separator for Capture Reactions (SECAR) is a new recoil separator currently under construction at the National Superconducting Cyclotron Laboratory (NSCL) and the Facility for Rare Isotope Beams (FRIB) that will allow us to directly measure the astrophysical reaction rates of interest. It is designed to enable measurements with reaccelerated beams in the A$=-65 mass range over a broad range of astrophysical energies. Several of the magnets and other components are now installed at Michigan State University. The presentation will introduce the SECAR concept, its scientific goals, and provide an update of the current status of the project. SECAR is supported by the Department of Energy Office of Science Office of Nuclear Physics and the National Science Foundation.

Rachel Titus, NSCL - "Impact of electron-captures on nuclei near N=50 on core-collapse supernovae"
Abstract: Sensitivity studies of the late stages of stellar core collapse with respect to electron-capture rates indicate the importance of a region of nuclei near the N=50 shell closure, just above doubly magic 78Ni. In the present work, it has been demonstrated that uncertainties in key characteristics of the evolution, such as the lepton fraction, electron fraction, entropy, stellar density, and in-fall velocity are about 50% due to uncertainties in the electron-capture rates on nuclei in this region, although thousands of nuclei are included in the simulations. The present electron-capture rate estimates used for the nuclei in this region of interest are primarily based on a simple approximation, and it is shown that the estimated rates are likely overestimated by an order of magnitude or more. More accurate microscopic theoretical models are required to obtain Gamow-Teller strength distributions, upon which electron-capture rates are based. The development of these models and the benchmarking of such calculations rely on data from charge-exchange experiments at intermediate energies, and an experimental campaign to study N=50 nuclei with the (t,3He) reaction at NSCL will be presented.

Steven A. Fromm, NSCL - "Improving the Optical Trapping Efficiency in the 225Ra Electric Dipole Moment Experiment via Monte Carlo Simulation"
Abstract: In an effort to study and improve the optical trapping efficiency of the 225Ra Electric Dipole Moment experiment, a fully parallelized Monte Carlo simulation of the laser cooling and trapping apparatus was created at Argonne National Laboratory and now maintained and upgraded at Michigan State University. The simulation allows us to study optimizations and upgrades without having to use limited quantities of 225Ra (15 day half-life) in the experiment's apparatus. It predicts a trapping efficiency that differs from the observed value in the experiment by approximately a factor of thirty. The effects of varying oven geometry, background gas interactions, laboratory magnetic fields, MOT laser beam configurations and laser frequency noise were studied and ruled out as causes of the discrepancy between measured and predicted values of the overall trapping efficiency. Presently, the simulation is being used to help optimize a planned blue slower laser upgrade in the experiment's apparatus, which will increase the overall trapping efficiency by up to two orders of magnitude.

Brent Glassman, NSCL- "β-delayed γ decay of 20Mg and the 19Ne(p,γ)20Na breakout reaction in Type I X-ray bursts"

Mean-field or energy density functional (EDF) methods have achieved a great success in describing many nuclear phenomena. Among the microscopic approaches to nuclear many-body problem, nuclear EDFs are the only ones that can be applied to study nuclei over the entire chart with a few universal parameters at acceptable computational costs. To go beyond the modeling of nuclear bulk properties and perform detailed calculations for nuclear excitations, one of the choices is to extend the mean-field approaches from the single-reference framework to a multi-reference one with generator coordinate method (GCM). In this framework, the dynamical correlations related to the restoration of symmetries broken in mean fields and to the fluctuations of collective degree of freedom can be taken into account efficiently. Along this direction, the so-called multi-reference energy density functional (MR-EDF) approaches have been tremendously developed by implementing the GCM into different modern EDF calculations in the recent decade. This beyond mean-field approach provides an important theoretical tool to analyze the low-energy structure of nuclei with shape coexistence and shape transition. In the mean time, with the technique of similarity renormalization group (SRG), the (multi-reference) IMSRG starting from a simple mean-field state has been developed and turned out to be successful for both close- and open-shell nuclei based on the interaction from chiral effective field theory (EFT). The above achievements inspire us to combine the virtues of GCM and IMSRG to realize an ab-initio study the low-lying states of nuclei with complex shapes. During this talk, I may show several applications of the MR-EDF method based on a relativistic energy density functional to nuclear low-lying states and the computation of nuclear matrix elements for neutrinoless double beta decay. Besides, I will show some preliminary results towards our goal of extending the MR-IMSRG approach for deformed/transitional nuclei using the chiral-EFT Hamiltonians.

The nuclear incompressibility parameter is one of three important components characterizing the nuclear equation of state. It has crucial bearing on diverse nuclear and astrophysical phenomena, including radii of neutron stars, strength of supernova collapse, and collective flow in medium- and high-energy nuclear collisions. The only direct experimental measurement of this quantity comes from the compression-mode giant resonances -- the isoscalar giant monopole resonance (ISGMR) and the isoscalar giant dipole resonance (ISGDR). There have been some experimental results recently suggesting that nuclear structure effects may influence the energy of the isoscalar giant monopole resonance and, hence, the nuclear incompressibility. However, this being a bulk property of nuclear matter, one expects structure effects to play no role in it. In this talk, I will review the current status of determination of nuclear incompressibility, and critically examine how, and if, nuclear structure effects play a role.

Alex Brown, FRIB- Microscopic calculations of nuclear level densities with the Lanczos method Vladimir Zelevinsky, FRIB- “Constant temperature model of the level density and attempts to understand its physical meaning”

The origin of the heaviest elements has long been one of the greatest mysteries of nuclear astrophysics. The only known means to synthesize nuclei up to uranium and thorium is rapid neutron capture, or r-process, nucleosynthesis, and exactly where and how the r-process occurs has remained uncertain for decades. Recently disparate lines of evidence---from astronomical observations, modeling of galactic chemical evolution and individual astrophysical events, neutrino and nuclear experiment and theory, and gravitational wave detections---appear to be converging on a preferred site of production: neutron star mergers. Here we will review the available evidence and discuss the role nuclear physics can play in a definitive resolution to this mystery.

The lecture will give an overview of some of the potential scientific discoveries that will be possible once the Facility for Rare Isotope Beams (FRIB) is completed. Topics include the origin of the chemical elements, atomic nuclei, and the forces that create the matter around us. Learn more about the MSU Science Festival at sciencefestival.msu.edu.

In the current multi-messenger era, a multitude of observational information offers exciting opportunities to piece together an answer to the puzzle of the synthesis of the elements. Such efforts many times depend critically on the microphysics input and particularly on our ability to reproduce in nucleosynthesis calculations intricate features of abundance yield patterns in order to evaluate the yield outcome of various scenarios. For such comparisons to be meaningful, however, uncertainties in the nuclear input that affect nucleosynthesis calculations have to be identified and their effect evaluated. In this talk, I take a look at the sources of uncertainty that are most influential to the extrapolation of Hauser-Feshbach calculations away from stability and trace them back to the modeling of statistical properties such as level densities and gamma-ray strengths. An attempt at the quantification of uncertainties in Hauser-Feshbach theory extrapolations is presented together with examples of the ways such studies can inform experimental and theoretical work in Nuclear Astrophysics.

One of the main goals of electronic structure theory is precise ab initio description of increasingly complex polyatomic systems. It is generally accepted that size extensive methods based on the exponential wave function ansatz of coupled-cluster (CC) theory are excellent candidates for addressing this goal. Indeed, when applied to molecular properties and chemical reaction pathways, the CC hierarchy, including CCSD, CCSDT, CCSDTQ, etc., rapidly converges to the limit of the exact, full configuration interaction (CI) diagonalization of the Hamiltonian, allowing one to capture the relevant many-electron correlation effects in a conceptually straightforward manner through particle-hole excitations from a single Slater determinant. One of the key challenges has been how to incorporate higher-than-two-body components of the cluster operator, needed to achieve a quantitative description, without running into prohibitive computational costs of CCSDT, CCSDTQ, and similar schemes, while eliminating failures of the more practical perturbative approximations of the CCSD(T) type in multi-reference situations, such as chemical bond breaking. A similar challenge applies to other areas of many-body theory, where CC methods have demonstrated considerable promise and where higher-than-two-body clusters are important, such as nuclear physics. In this talk, I will discuss a radically new way of obtaining accurate energetics equivalent to high-level CC calculations, even when electronic quasi-degeneracies and higher–than–two-body clusters become significant, at the small fraction of the computational cost, while preserving the black-box character (minimum input information) of conventional single-reference computations. The key idea is a merger of the deterministic formalism, abbreviated as CC(P;Q) [1-4], with the stochastic CI [5,6] and CC [7–9] Monte Carlo approaches [10,11]. The advantages of the proposed methodology will be illustrated by a few molecular examples, where the goal is to recover highly accurate full CCSDT and CCSDTQ energetics, including bond breaking in F2 and H2O and automerization of cyclobutadiene. [1] J. Shen and P. Piecuch, Chem. Phys. 401, 180 (2012). [2] J. Shen and P. Piecuch, J. Chem. Phys. 136, 144104 (2012). [3] J. Shen and P. Piecuch, J. Chem. Theory Comput. 8, 4968 (2012). [4] N.P. Bauman, J. Shen, and P. Piecuch, Mol. Phys. 115, 2860 (2017). [5] G.H. Booth, A.J.W. Thom, and A. Alavi, J. Chem. Phys. 131, 054106 (2009). [6] D. Cleland, G.H. Booth, and A. Alavi, J. Chem. Phys. 132, 041103 (2010). [7] A.J.W. Thom, Phys. Rev. Lett. 105, 263004 (2010). [8] R.S.T. Franklin, J.S. Spencer, A. Zoccante, and A.J.W. Thom, J. Chem. Phys. 144, 044111 (2016). [9] J. S. Spencer and A. J. W. Thom, J. Chem. Phys. 144, 084108 (2016). [10] J.E. Deustua, J. Shen, and P. Piecuch, Phys. Rev. Lett. 119, 223003 (2017). [11] J.E. Deustua, J. Shen, and P. Piecuch, in preparation.

The National Science Foundation (NSF) is the primary agency within the US Government that is devoted to funding university-based basic research in all fields of science and engineering. Funds provided through NSF awards provide both infrastructure resources and support for students and postdoctoral research associates engaged in the research projects. The presentation will discuss the structure and goals of the agency and describe a little of what it is like to work there.

In 1958 a Cyclotron Laboratory was established at MSU, with the goal of building a cyclotron accelerator and strengthening the research program in nuclear physics. This talk will describe how this laboratory grew from one researcher, its director Henry Blosser, until it could compete successfully for the right to build FRIB, a device at the world forefront in nuclear physics. The story revolves around the set of people, attitudes, goals, and scientific culture that led to this improbable success. Learn more about the MSU Science Festival at sciencefestival.msu.edu.

The dependence of statistical properties of nuclei on intrinsic deformation is an important input to dynamical nuclear processes such as fission. The auxiliary-field Monte Carlo (AFMC) method is a powerful technique for computing statistical properties of nuclei. However, the statistical distribution of intrinsic shapes is not readily accessible due to the formulation of AFMC in a spherical configuration-interaction shell-model approach. Instead, theory of deformation up to now has largely relied on a mean-field approximation which breaks rotational symmetry. We present a novel method for calculating the statistical distributions of intrinsic deformation within the rotationally invariant framework of the shell model, and show results for spherical, transitional, and strongly deformed nuclei.

Halo nuclei are radioactive nuclei, which exhibit an uncommon nuclear structure: their matter radius is much larger than that of stable nuclei. This large size is qualitatively understood as due to their low separation energy for one or two neutrons. Thanks to this loose binding, these valence neutrons exhibit a high probability of presence at a large distance from the other nucleons. They thus form a sort of diffuse halo around a compact core. The best known examples are 11Be, with a one-neutron halo, and 11Li, with a two-neutron halo. Due to their short lifetime, these nuclei are mostly studied at RIB facilities through reactions, like breakup. In order to extract valuable structure information from measured cross sections, a precise model of the collision coupled to a reliable description of the projectile is needed. Many such models have been developed for breakup. However, they mostly rely on a simple two- or three-body description of the nucleus. Recently, 11Be has become accessible to ab initio calculations. Unfortunately, such an A-body description is too computationally demanding to be directly included within existing reaction models. During this seminar, I will explain how we can use the Halo effective field theory to constrain the description of halo nuclei within a reliable breakup model from the outputs of ab initio calculations. The results obtained for the breakup of 11Be on Pb and C at 70AMeV are in excellent agreement with experimental measurements. This not only proves the feasibility of incorporating predictions from ab initio calculations in reaction theory, but, more importantly, they confirm the results for important aspects of the structure of 11Beobtained by the ab initio calculation of Calci et al.

We propose a new method for measuring the rate of rare nuclear reactions by capturing the heavier atomic products in a noble gas solid. Once embedded in the transparent noble gas matrix, the products are selectively identified via laser fluorescence spectroscopy and individually counted via optical imaging to determine the reaction rate. Single atom sensitivity is feasible due to the noble gas matrix facilitating a Stokes shift between the emission and excitation spectrum of the product atoms, granting the possibility to carefully filter out the excitation light. The combination of a recoil separator for isotopic selectivity and reduction of beam induced heat load, and the tools and techniques from the fields of single molecule spectroscopy and superresolution imaging allows for a detecting scheme with near unity efficiency, a high degree of selectivity, and single atom sensitivity. The Single Atom Microscope could be used to measure a number of astrophysically relevant nuclear reaction rates.

50 years after their discovery, neutron stars are poised to take center stage in this era of multi-messenger astrophysics. I will highlight advances in theory and mention some key observations that have provided fundamental new insights about neutron star properties and their central role in nuclear astrophysics. I will discuss how neutron stars, and extreme phenomena involving them, can serve as laboratories to study dense matter, neutrinos, axions and dark matter.

The Cryogenic Underground Observatory for Rare Events (CUORE) is the first tonne-scale bolometric experiment searching for neutrinoless double beta decay. The detector consists of an array of 988 TeO2 crystals arranged in a cylindrical compact structure of 19 towers. After the completion of the detector construction in August 2016, CUORE was successfully cooled down to a base temperature below 8 mK by the beginning of 2017. Following an intense period of detector commissioning and optimization, the first physics data were taken in May-September 2017, resulting in the most stringent limits to date on the neutrinoless double-beta decay of Te-130. We will describe the performance of the CUORE cryostat and the detector systems and discuss the first physics results from CUORE. We will also discuss a follow-up program, dubbed CUPID (CUORE Upgrade with Particle ID), a proposed next-generation bolometric experiment that aims to improve the sensitivity to 0nuDBD rate by another order of magnitude, and to be able to discover this rare process if it is consistent with the inverted hierarchy of neutrino masses.

Committee: Witold Nazarewicz (Chairperson), S. Balasubramaniam, A. Brown, D.Lee, B. O'Shea

The recent observations of the GW170817 electromagnetic counterpart suggest lanthanides were produced in this neutron star merger event. However many questions regarding heavy element production in mergers remain: can such events account for all the r-process lanthanide material observed in the galaxy? are precious metals such as gold produced in sufficient amounts? are actinides produced? where within the merger environment does nucleosynthesis occur and under what specific conditions? Such questions can only be answered with careful studies of the nuclear physics uncertainties affecting r-process calculations. Here I will discuss recent extended calculations of beta-delayed fission and their implications for r-process nucleosynthesis. The influence of fission fragment distributions will also be addressed with a particular emphasis on the unknown origin of the r-process rare-earth peak at A~164. Since the rare-earth peak is formed as the r-process path begins to draw closer to stability, the rare-earth nuclei contributing to peak formation will soon be within reach of nuclear physics experiments performed at, for example, the CPT at CARIBU and the upcoming FRIB. Here I will present the latest results for the masses found to produce the rare-earth peak in a low entropy accretion disk wind scenario and compare directly with recent mass measurements from the CPT at CARIBU. Such collaborative efforts between theory and experiment could soon be in a position to make definitive statements regarding the mechanism of rare-earth peak formation and thus the astrophysical site of the r process.

The SuN Tape system of Active Nuclei (SuNTAN) has been developed at the NSCL to be integrated with the Summing Na(I) (SuN) detector for sensitive gamma spectroscopy with radioactive beams. SuNTAN consists of a movable metallic tape and a beta-sensitive scintillator detector. Low-energy beams from the NSCL gas stopping area can be very pure, thus, a majority of the detected beta-decays will be from the implanted ions. However, the daughter nuclei in the decay chain present an unwanted, often significant, source of radiation. Spectroscopy on the implanted ions requires these daughter products either be accounted for, or reduced. SuNTAN is able to remove daughter and granddaughter activities, decreasing detection of these contaminants. Measurements with SuN and SuNTAN will be used for total absorption spectroscopy (TAS), a powerful technique used to find beta-decay intensities, and used with the beta-Oslo method to constrain neutron-capture reactions. This talk will present first results from the commissioning experiment of SuNTAN and plans for future experiments.

COMMITTEE: Christopher Wrede(Chairperson), L. Chomiuk, J. Huston, S. Pratt, R. Ringle

NS3 is a summer school for undergraduate students that aims to introduce the participants to the field of nuclear science. NS3 will be hosted by Michigan State University (MSU) and will offer lectures and hands-on activities covering selected nuclear science topics. The school activities will take place at the National Superconducting Cyclotron Laboratory (NSCL) and will include lectures by local and visiting researchers, nuclear physics labs, a tour of the facility, discussions with graduate students and faculty, and more.

Committee:Hironori Iwasaki(Chairperson),A. Gade S. Liddick, F. Nunes, P. Zhang

Fission is an important decay mode for super-heavy nuclei and nuclei of astrophysical importance. In addition, fission fragment mass distribution can be used as a probe to study the nuclear behavior away from the stability line in the sub-lead region. The theoretical progresses in both of these fields and the associated future perspectives will be discussed in the present seminar. Specifically, the theoretical method to calculate the fission fragment mass distribution and the role of nuclear localization functions to simulate the structural evolution of a fissioning system will be elaborated.

Nuclear non-proliferation has taken on renewed intensity with changing world events. As deals are negotiated and renewed, human rights advocates raise concerns about political prisoners, many of whom are academics, languishing in prisons around the world. The modern history of physics and human rights will be discussed before focusing on recent violations of these rights. Some cases include: Omid Kokabee, an Iranian studying physics at the University of Texas-Austin who was in an Iranian prison for five years for refusing to engage in scientific research he deemed harmful to humanity; Xiaoxing Xi, a Temple University Professor whose human rights were violated by the United States on accusations of spying for a foreign government; the current persecution of Turkish scientists, and other recent cases as time permits. Suggestions will also be made on how individuals can become involved in these issues.

Enjoy free concerts in 1300 FRIB Laboratory. The free musical performances showcase faculty, students, and guests of the Michigan State University College of Music and the Greater Lansing music community. For permit and metered parking information, visit the Parking page.

COMMITTEE: ManYee B. Tsang, Chairperson Norman Birge Edward Brown William Lynch Wolfgang Mittig Thesis is on display in 1312 BPS bldg. and the NSCL atrium

COMMITTEE: Alexandra Gade, Chairperson D. Bazin B. Alex Brown S. Liddick K. Tollefson

Enjoy free concerts in 1300 FRIB Laboratory. The free musical performances showcase faculty, students, and guests of the Michigan State University College of Music and the Greater Lansing music community. For permit and metered parking information, visit the Parking page.

COMMITTEE: Georg Bollen, Chairperson Alexandra Gade David Morrissey Stuart Tessmer Vladimir Zelevinsky Thesis is on display in 1312 BPS bldg. and the NSCL atrium

Ahead of an upcoming national screening tour, you're invited to experience a digital presentation of Humanity Needs Dreamers: A Visit With Marie Curie (40 mins) with filmmaker Jen Myronuk on Wednesday, July 25th at 5:30pm. As one of the world’s most renowned scientists, two-time Nobel Prize winner Marie Sklodowska Curie is best known for pioneering the field of radioactivity — but few understand the obstacles she faced just to get into the laboratory. What if she could tell her story? Written and portrayed by engineer & scholar Susan Marie Frontczak and produced by STEM on Stage, this presentation is part of an NSF-funded collaborative outreach study with Princeton Center for Complex Materials with preview screenings at PCCM, MIT Kavli Institute & MIT Department of Physics, Johns Hopkins University Applied Physics Lab, Cambridge Science Festival among others along with formal presentations at APS Physics and ACS. humanityneedsdreamers.org

COMMITTEE: Artemis Spyrou (Chairperson), Norman Birge, Edward Brown, Morten Hjorth-Jensen, Sean Liddick Thesis is on display in 1312 BPS bldg. and the NSCL atrium

The quantum laws governing atoms and other tiny objects seem to defy common sense, and information encoded in quantum systems has weird properties that baffle our feeble human minds. John Preskill will explain why he loves quantum entanglement, the elusive feature making quantum information fundamentally different from information in the macroscopic world. By exploiting quantum entanglement, quantum computers should be able to solve otherwise intractable problems, with far-reaching applications to cryptology, materials, and fundamental physical science. Preskill is less weird than a quantum computer, and easier to understand.

COMMITTEE: Georg Bollen, Chairperson O. Naviliat-Cuncic L. Roberts C. Ruan H. Schatz

The study of nuclei with large neutron to proton asymmetries is very useful to investigate the inter-action between neutrons and protons in extreme conditions which exist for instance in explosive stars. It could also improve our knowledge about new effects that occur when we move far from the stability. In a first part, I will present my recently published results [1] on the n-n correlations observed in the decay of unbound states in 18C and 20O (viewed as 14C+4n and 16O+4n, respectively) populated via the sudden knockout of a proton in 19N and a neutron in 21O. I will discuss a novel method that allows to reveal neutron correlations in the nucleus. This was achieved by studying the decay of high-energy states above S2n populated after the sudden knockout of a deeply bound nucleon. This experiment, performed at GSI, required the complex R3B-LAND setup to determine the full kinematics of the reaction. We have studied the evolution of the n-n correlations as a function of the increasing energy Ed of the system and compared the decay patterns of the two systems. We used a simulation that takes into account the different decay mechanisms (direct and sequential decay) and the final state interactions to interpret the experimental data. Using information on n-n and core-n momenta, we show that we can clearly distinguish direct from sequential decays. Remarkably, direct decay is strongly dominant in 18C up to Ed=8 MeV, beyond which sequential decay amounts to only 20%. This is in contrast to the case of 20O, in which sequential decay dominates already at low Ed, and in which much weaker n-n correlations are observed. In a second part, I will discuss the evolution of the p-n interaction towards the neutron dripline in the fluorine isotopic chain. Recent experiments have shown that the dripline occurs in the oxygen isotopes at the doubly magic 24O. However, with the exception of 28F and 30F, which are unbound, six more neutrons can be added in the fluorine isotopic chain before reaching the dripline at 31F. One can therefore speculate that the extension of the dripline between oxygen and fluorine, as well as the odd-even binding of the fluorine isotopes, arise from a delicate balance between two-body p-n and n-n interactions, the coupling to the continuum, and three-body forces. Within this context, we have investigated the evolution of the residual interaction between the 26F and 28F nuclei that were studied at RIKEN during the SAMURAI21 experiment. The setup benefited from some powerful and innovative devices, such as the NeuLAND demonstrator and the MINOS TPC. I will present the results on the structure of 26F unbound states populated via neutron knockout from 27F as well as the ground and first excited states of the unbound 28F, populated via knockout reactions from 29F and 29Ne at 250 MeV/nucleon. Our results complete previous studies on 26F, where bound excited states [2] and unbound states populated via proton knockout from 27Ne [3] have already been investigated. Moreover our results on 28F highly improve and complete a previous study [4] due to the high statistics and resolution achieved during this experiment. References [1] A. Revel et al., Phys. Rev. Lett. 120, 152504 (2018). [2] A. Lepailleur et al., Phys. Rev. Lett. 110, 082502 (2013). [3] M. Vandebrouck et al., Phys. Rev. C 96, 054305 (2017). [4] G. Christian et al., Phys. Rev. Lett. 108, 032501 (2012).

Nuclear Structure 2018 (NS2018) is the 17th in a series of nuclear structure conferences organized biennially by North American national laboratories. Previous meetings in this series have been held in Knoxville (ORNL), Vancouver (TRIUMF), Argonne (ANL), and Berkeley (LBL). These conferences are devoted to recent experimental and theoretical developments in the research on nuclei near the limits of isospin, spin and excitation energy. A high-resolution version of the conference poster can be downloaded here or through the menu. The Low Energy Community Meeting (LECM) 2018 will immediately follow NS2018. If you plan to attend any part of the LECM please register using the link on the left.

The 2018 Low Energy Community Meeting will be held on the campus of Michigan State University in East Lansing, Michigan. The meeting will immediately follow the Nuclear Structure 2018 Conference. https://indico.fnal.gov/event/15548/page/2

The recent technical upgrade of the large-scale experimental facilities combined with the boost in development of the advanced instrumentation (e.g. Ge tracking arrays), together with the quantitative and qualitative progress in the excellence of theoretical models, have resulted in remarkable gains in our understanding of the structure of the atomic nucleus. Thanks to the expected completion of the large RIB facilities in the USA and in Europe the following decade will bring us even closer to the frontiers of the nuclear physics. The essential information on the single-particle energies and two-body residual interactions can be derived from the experimental observables, such as excitation energies and reduced transition probabilities, and it can be used to estimate the nuclear structure of more complex configurations. Transition probabilities, especially B(E2) values, give particularly valuable insights into the nature of nuclear collectivity and its evolution with respect to the neutron and proton numbers. For almost all the even-even nuclei and in particular for those near the shell closures, while augmenting the number of valence nucleons from the shell closure, the reduced transition probability B(E2; 2 +→0+) increases progressively until a maximum value is reached around the mid-shell, where the number of degrees of freedom is maximum. The deviation from this parabolic behavior could be a fingerprint of the creation/disappearing of a shell closure or of the presence of other phenomena, such as shape coexistence. In this work the evolution of the collectivity has been studied via lifetime measurements in two crucial neutron-deficient regions which present a flatter trend of the B(E2; 2+→0+). In the first case, the robustness of the proton shell closure Z=50 has been investigated in the exotic nuclei towards doubly-magic 100Sn. In order to overcome the experimental limitations induced by the presence of low-lying isomers along the whole Sn isotopic chain and also to provide complementary information to the existing Coulomb excitation measurements, the lifetime of the 21+ and 41+ excited states were measured for the first time in 106,108Sn via the Recoil-Distance Doppler-Shift (RDDS) method, populating the nuclei of interest via a multi- nucleon transfer reaction. Thanks to the crucial role of the measured B(E2; 4+→2+) values, the comparison between the new experimental results with the state-of-the-art Large-Scale Shell-Model (LSSM) calculations has shown for the first time the limitation of the seniority truncation approach and the need of an extended valence space to correctly describe the region. In the second case, the shape coexistence has been studied in the neutron-deficient nuclei in the vicinity of Z=82 shell closure. In particular, the systematic studies of the low-lying structures of mercury isotopes have indicated 188Hg to be the heaviest isotope manifesting the fingerprints of this phenomenon. However, the information on the electromagnetic properties of low-lying states in this isotope is scarce or absent. Thus, the measurement of the lifetimes of excited states in 188Hg is of a great interest for a better comprehension of the evolution of the collective properties in this mass region. The preliminary experimental results have been compared with the state-of-the-art beyond mean-field calculations performed with the symmetry-conserving configuration-mixing method, which confirms the coexistence of two deformed structures for the nucleus of interest.

COMMITTEE: Georg Bollen, Chairperson K. Minamisono S. Pratt A. Spyrou S. Tessmer

The search for the electric dipole moment (EDM) of molecules, atoms, nuclei, and elementary particles have yielded only null results over the past sixty plus years. EDMs are a direct indication of both time-reversal and parity violation as well as a compelling signature of charge-parity violation. For this reason they are thought to play a crucial role in understanding the apparent scarcity of antimatter in the visible Universe. Because the EDM of particles within the Standard Model are expected to be very small, any observation of an EDM for the foreseeable future would be clear signal of physics beyond the Standard Model. I will review the landscape of EDM searches as well as discuss specific opportunities in the FRIB era.

The history and the present-day status of the OpenXAL application software environment for the SNS accelerator are discussed. The OpenXAL/XAL components, their interactions, and implementation details are described. The functionality and algorithms of the Superconducting Linac (SCL) Tuning Wizard application which automates the SNS SCL RF cavities tuning are presented.

We demonstrate that the intricate energy spectrum of neutron-rich helium isotopes can be straightforwardly described by taking advantage of the low-energy properties of neutron-neutron interaction and the scale separation that is present in diluted dripline systems. By using arguments based on the halo effective field theory, we carry out a parameter reduction of the complex-energy configuration interaction framework in the spd space, including resonant and scattering states. By constraining the core potential to alpha-n scattering phase-shifts and adjusting the strength of the spin-singlet central neutron-neutron interaction, we reproduce experimental energies and widths of 5-8He within tens of keV precision. We predict a parity inversion of narrow resonances in 9He and show that the ground state of 10He is an s-wave-dominated configuration that could decay through two-neutron emission. This threshold state can be viewed as a ``double-halo" structure in an analogy to the atomic 3He(4He)2 trimer.

COMMITTEE: Artemis Spyrou(Chairperson), J. Huston S. Liddick, H. Schatz, V. Zelevinsky

We present a Bayesian machine learning methodology designed to refine and quantify theoretical mass predictions in extreme extrapolations, taking advantage of the information contained in the discrepancies between the mass model and the experimental information where it exists. Our methodology is developed on ten global mass models for the two-neutron separation energies of even-even nuclei. Quantified emulators of one- and two-neutron separation energies residuals are then constructed using Bayesian Gaussian processes and applied to derive the probability for nuclides to be bound to neutron emission. The recent discovery of the extremely neutron-rich nuclei around 60Ca and the experimental determination of masses for 55-57Ca provide unique new information about the binding energy surface in this region. In particular, considering the current experimental information, we predict that 68Ca has an average posterior probability pex ≅ 76% to be bound to two-neutron emission while 70Ca is a threshold system with pex ≅ 57%. 61Ca is expected to decay by emitting a neutron (pex ≅ 46%).

The discovery of the important neutron-rich nucleus 60Ca and seven others near the limits of nuclear stability is reported from the fragmentation of a 345 MeV/u 70Zn projectile beam at the radioactive ion-beam factory of the RIKEN Nishina Center. The produced fragments were analyzed and unambiguously identified using the BigRIPS two-stage in-flight separator. The results are compared with the drip lines predicted by a variety of mass models and it is found that the models in best agreement with the observed limits of existence in the explored region tend to predict the even-mass Ca isotopes to be bound out to at least 70Ca. The potential for the synthesis of such super neutron-rich calcium isotopes at FRIB will be discussed.

Inclusive electron scattering experiments using fixed targets are an important tool for studying the structure of complex objects such as the nucleons. Interestingly, the inelastic structure of the nucleon is known to be modified inside the nuclear medium. This modification, called the European Muon Collaboration (EMC) effect, can be studied using inclusive Deep Inelastic electron-nucleus scattering. Recent evidence suggests that the EMC effect may arise due to nucleon Short Range Correlations (SRC). In this presentation, I will discuss new measurements of the EMC effect and SRC pair abundances conducted at the Thomas Jefferson National Accelerator Facility. In addition, I will present a data-driven, SRC-based phenomenological model of the EMC effect which can consistently describe the effect across nuclei.

All scientists, postdocs and graduate students interested in research and development related to ion optical devices and their scientific exploitation are encouraged to attend. There is no registration fee for students and postdocs.

Understanding the origin of the elements is one of the major challenges of modern astrophysics. The rapid neutron-capture process, or r-process, is one of the fundamental ways that stars produce the elements listed along the bottom two-thirds of the periodic table, but key aspects of the r-process are still poorly understood. I will describe four major advances in the last few years that have succeeded in confirming neutron star mergers as an important site of the r-process. These include the detection of freshly produced r-process material powering the kilonova associated with the merger of neutron stars detected via gravitational waves (GW170817), the identification of a dwarf galaxy where most of the stars are highly enhanced in r-process elements (Reticulum II), new connections between the r-process and its Galactic environment (thanks to data from the Gaia satellite), and advances in deriving abundances of previously-undetected r-process elements (such as Se, Te, Pt) in ultraviolet and optical spectra of metal-poor stars. I will highlight opportunities to connect these research directions with future facilities (like FRIB, CETUS, and HabEx) to associate specific physics with specific sites of the r-process.

Nb3Sn is a promising future material for superconducting radiofrequency (SRF) cavities. It requires R&D to develop fully for applications, but it already shows high Q0 at relatively high temperatures including near 4 K, and predictions suggest that its ultimate accelerating gradient limit would be significantly higher than that of niobium. Fermilab recently started a Nb3Sn SRF cavity development program, with the goals of pushing performance and scaling up from R&D-style cavities to production-style cavities. In this presentation, I overview the coating process, parameter exploration to achieve high quality films, single-cell 1.3 GHz cavity performance, and first exploration of cavities beyond 1.3 GHz single cells.

Enjoy free concerts in 1300 FRIB Laboratory. The free musical performances showcase faculty, students, and guests of the Michigan State University College of Music and the Greater Lansing music community. For permit and metered parking information, visit the Parking page

A theory for computing cross sections for inclusive A(d,p)X processes has been previously developed [1]. This includes direct neutron transfer to bound states, transfer to the continuum, as well as inelastic processes. Therein, local optical potentials are used to describe the nucleon-target interaction. We extend this framework to investigate the effects of nonlocality in the optical potentials for A(d,p)X reactions populating neutron bound and scattering states. We obtained neutron wave functions for nonlocal interactions of the Perey-Buck type within the R-matrix method [2]. Here, I will discuss the A(d,p)X processes on 16O, 40Ca, 48Ca and 208Pb at 10, 20 and 50 MeV.

Studies on electron-positron linear colliders started in mid 1980s in various labs world-wide. They were unified in the name of ILC (International Linear Collider) in 2004 and a new organization GDE was formed immediately. The GDE published the TDR (Technical Design Report) in 2013 and passed the work to the LCC (Linear Collider Collaboration). Japanese scientists raised their hands to build it in Japan and Japanese Government has been discussing about its approval since the TDR publication. Some sort of decision by the government will be made by the end of this year. In this seminar, design features of the ILC with technology issues will be explained together with the recent movements of the MEXT (Ministry of Education and Science) and the Science Council of Japan.

Observation of neutrinoless double-beta decay would both demonstrate the Majorana nature of the neutrino and provide experimental access to its absolute mass scale. Over the last decade, wavefunction contributions for leading neutrinoless double-beta decay candidates have been probed in a campaign of experiments utilizing transfer reactions to determine nucleon occupancies in a consistent way. While these studies have provided a great deal of information for comparison with theory, especially on contributions to the nuclear wavefunctions from competing orbitals, they lack sensitivity to the collective and shape degrees of freedom which have been shown to be an integral part of the structure of parent-daughter nuclei relevant to neutrinoless double-beta decay. In this talk, I will present results of highprecision Coulomb excitation measurements aimed at studying the various collective-shape degrees of freedom and associated phenomena. The talk will focus primarily on the electromagnetic properties of low-lying states in 72,76Ge which were investigated via multistep Coulomb excitation using the advanced gamma-ray tracking array, GRETINA and the charged particle detector, CHICO2. The influence of axial asymmetry parameter on the shape of these nuclei along with the results of multi-configuration mixing calculations carried out within the framework of the triaxial rotor model will highlighted. Most importantly, the results on 76Ge will be compared with state-of-the-art shell model calculations and recently obtained (n,n'[gamma]) data, with emphasis on demonstrating the importance of nuclear deformation in determining the nuclear decay matrix elements.

Tommy Tsang- Neutron star properties from gravitation wave and nuclear physics constraints and Linda Hlophe- Few-body universality in the deuteron-alpha system

Accelerator modeling has long relied on symplectic integration for tracking particles. However, in cases with strong space charge, symplectic maps are not available. Recent work indicates that symplecticity is not needed, that simple volume preservation is sufficient. To this end, we have developed a volume preserving particle push that is shown to have excellent phase-space preservation properties, which we expect to be advantageous for self-consistent (significant space-charge) beams. As a second part of this talk, we will discuss recent developments in collisional interactions within the VSim framework, which may have use for FRIB, including for beam-gas interactions. The new framework has been designed to be GPU ready, and it has been validated for collisional dynamics.

The recent aLIGO/aVirgo discovery of the gravitational wave from the neutron star merger (NSM) GW170817, and the follow up kilonova observations have shown that NSMs produce copious amount of r-process material. Assuming neutron star mergers are the dominant sources of r-process elements in the universe, we study the chemical evolution of the Milky Way and ultra faint dwarf (UFD) galaxies through a novel set of zoom cosmological simulations. Our results indicate that fast merging channels of neutron star binaries are required in order to explain the observed statistics of the r-process enriched UFDs and metal poor r-process enhanced stars in the MW's halo. Moreover, in order to explain the r-process UFDs statistics, these systems should have lost a significant fraction of their stellar mass. Two candidate fast merging channels for the NSBs would be: (i) those on highly eccentric orbits, and (ii) those assembled through case BB unstable mass transfer. I discuss the implications of existence of such channels for GW detectors.

The γ-ray energy spectrum of the 3H(d,γ)5He reaction and the (d,γ)/(d,n) branching ratio for 3H+d fusion are important for basic nuclear science in unbound systems as well as inertial confinement fusion (ICF) diagnostic development. Both quantities were measured at the Edwards Accelerator Laboratory on the campus of Ohio University using the 4.5-MV tandem accelerator with a pulsed deuteron beam impinging upon a thick titanium tritide target by measuring the resultant γ-rays, neutrons, and α-particles. Major ICF facilities such as the National Ignition Facility (NIF) and the Laboratory for Laser Energetics (LLE) use signatures of the 3H(d,γ)5He reaction, as well as other nuclear reaction signatures as diagnostic tools for monitoring implosion performance. One such diagnostic, the Magnetic Recoil Spectrometer for time-resolved neutron measurements (MRSt), is currently being designed as the first diagnostic capable of measuring time-resolved neutron spectra of ICF implosions. Results from key off-line tests for the feasibility of the system, including the implementation of a deuteron conversion foil fielded on the hohlraum and testing the response of lead-free microchannel plates to 14-MeV neutrons will be presented. In addition, a brief overview of other accelerator-based measurements of reactions of ICF relevance and ICF-based measurements of basic nuclear physics will be discussed.

I review the current status of the effort to make new superheavy nuclei. I discuss the evolution and status of the Periodic Table. The current methods of synthesizing new heavy nuclei and the production of the outcomes of heavy element synthesis are presented. New opportunities for heavy element synthesis involving multi-nucleon transfer reactions and reactions using radioactive beams will be discussed.

S. Lyons, A. Spyrou, S.N. Liddick, B.P. Crider, F. Naqvi, A.C. Dombos, D.L. Bleuel, B.A. Brown, A. Couture, L. Crespo Campo, J. Engel, M. Guttormsen, A.C. Larsen, R. Lewis, P. Moller, S. Mosby, M. R. Mumpower, E. Ney, A. Palmisano, G. Perdikakis, C.J. Prokop, T. Renstrom, S. Siem, M. K. Smith, and S. J. Quinn The rapid neutron-capture process, or r process, is known to produce roughly half of the isotopes of heavy elements. Sensitivity studies have shown that the final abundance distributions of r-process nuclei are greatly impacted by uncertainties in nuclear masses, neutron-capture rates, and β-decay properties. For this reason, β-decay intensities for 69,71Co were measured using the technique of total absorption spectroscopy at the NSCL. This technique allows us to overcome the so-called “pandemonium effect,” which can cause β-feeding intensities to high-lying excitation energies to be missed in traditional β-decay experiments. The high Q-value of these isotopes allows for the study of β-decay properties over a broad energy range. The resultant β-decay intensities and deduced Gamow-Teller strengths will be compared to theoretical models, which are commonly used in r-process calculations.

The unitary Fermi gas, situated right in the middle of the crossover between Bardeen-Cooper-Schrieffer superfluidity and Bose-Einstein condensation, is one of the most intensely studied many-body system in recent years. However, its strongly-correlated nature renders a theoretical treatment challenging. While the spin-balanced scenario is accessible with Quantum Monte Carlo methods, its spin-imbalanced counterpart suffers from a sign problem and is thus out of reach for such approaches. Recently, the complex Langevin method was adapted to non-relativistic theories. With this method at hand, we are now able to treat spin-polarized fermions at unitarity in an ab initio fashion and extract thermodynamic properties such as the particle density and magnetization. From equations of state, we obtain response functions such as the compressibility and magnetic susceptibility. In the spin-balanced case, we observe excellent agreement of our non-perturbative results with existing state-of-the-art results from other methods as well as with experimental data. At low fugacity, we find excellent agreement with the virial expansion for spin-polarized systems. Away from the limit where the virial expansion is valid, we provide predictions for the equations of state for a wide range of spin asymmetries. In the fully quantum mechanical regime close to the balanced limit, our results suggest that the critical temperature for the superfluid transition depends only weakly on the spin polarization.

The inspiral of a neutron star into the center of its stellar companion was proposed as a way to produce a long-lived giant star, powered by the energy released as matter slowly accretes onto the neutron star (a Thorne-Zytkow object). However, it was realized in the 90s that these neutron stars would accrete rapidly, radiating their energy in neutrinos. These neutron star inspirals are now considered to be progenitors of ultra-long gamma-ray burst models and may possibly eject neutron rich yields into the universe. In this talk, I will review the physics behind the fate of neutron star inspirals and then discuss the resultant prospects in transient astronomy and galactic chemical evolution.

High-energetic protons and secondary particles induce in matter the production of a big variety of radionuclides, some of them being very rare, exotic, and, in several cases, difficult to obtain by complementary reactions. These isotopes are of high importance in research fields like nuclear astrophysics, basic nuclear physics or environmental science, and sufficient sample material for scientific experiments is urgently needed. Highly-activated components stemming from the surroundings or parts of a high-power particle accelerator are a unique possibility to gain such valuable isotopes. The advantage of “mining” isotopes from waste materials consists in their principal availability, not requiring “extra” beam time. The challenge is their radiochemical isolation from the matrix. PSI operates the Spallation Neutron Source SINQ, which is driven by one of the most powerful high-energetic proton accelerators world-wide (590 MeV, up to 2.4 mA), and is therefore best-suited as a producer of such rare exotic radionuclides. In the frame of the ERAWAST (Exotic Radionuclides from Accelerator Waste for Science and Technology) initiative a complex program for isotope separation from different matrices has been established at PSI within the past decade. The talk presents an overview on the isotope resources at PSI, the methods for isolation and sample preparation as well as some of the highlights in scientific application.

*** Jeremy Lantis, NSCL- Development of Optical Pumping Technique for Determination of Charge Radii and Nuclear Moments for Fe and Zr isotopes *** Andrew Miller, NSCL- Charge radii of neutron-deficient 36,37,38Ca *** Katherine Childers, NSCL- Constraining the cross section of 82Se(n, γ)83Se to validate the β-Oslo method *** Rebecca Lewis, NSCL- Experimentally constrained 70Ni(n,γ)71Ni cross section *** Alicia Palmisano, NSCL- Cross Section Measurements of 84Kr(p,γ)85Rb *** Lisa Carpenter, NSCL- Cluster Structure and Three-Body Decay of 14C *** John Ash, NSCL- Nuclear Spectroscopy of 44,46Ca with Fusion Reactions Induced by Reaccelerated Rare-isotope Beams *** Robert Elder, NSCL- Reaction and lifetime studies of 32Mg through 2-proton knockout *** Dayah Chrisman, NSCL- Neutron Unbound States in the Island of Inversion *** Daniel Votaw, NSCL- Measurement of 9He ground and excited states ***

COMMITTEE: Christopher Wrede, Chairperson B. Alex Brown Laura Chomiuk Wade Fisher Artemis Spyrou Thesis is on display in 1312 BPS bldg. and the NSCL atrium

This presentation covers the implementation and results from the first complete six-dimensional phase space measurement of a beam in a hadron accelerator. The measurement was made on the Spallation Neutron Source Beam Test Facility, a functional duplicate of the SNS front-end. The data reveal previously unknown correlations in the six-dimensional phase space distribution that are not visible in lower dimensionality measurements. These correlations are shown to be intensity dependent.

The excited spectrum of hadrons is a spectrum of rapidly decaying resonances whose existence we infer from observations of their decay products. The underlying theory of quark and gluons, QCD, can be studied numerically using lattice techniques where the fields are considered on a grid of finite size. I will describe how we can make use of the finite box in which lattice QCD calculations are performed to learn something about hadron scattering amplitudes from first principles. These amplitudes contain information about the resonance structure of QCD and hence the spectrum of excited mesons and baryons. I will present the results of recent calculations in which the lightest scalar, vector and tensor mesons have been studied.

*Ryan Connolly (Physics & Astronomy Dept, MSU) - Signatures of exotic matter in the deep neutron star crust *Bill Lynch (NSCL, MSU) - Crust-core transition in neutron stars

Without short range interaction, the Pauli exclusion principle causes the majority nucleons (usually neutrons) in an asymmetric nucleus to have higher average momentum than the minority. High-energy electron scattering measurements showed that the short range interaction between the nucleons mainly form correlated high momentum neutron-proton pairs in the nucleus. Thus, in neutron-rich nuclei, protons have greater probability than neutrons to have momentum larger than the Fermi momentum. Based on our new data from CLAS detector at Jefferson Laboratory we claim that this results in protons having higher average momentum than neutrons, i.e., an inversion of the momentum sharing between majority and minority nucleons. Moreover, as we add more neutrons, the fraction of correlated protons increases whereas that of the neutrons stays constant. These results have several implications, starting from medium modification (the EMC effect), and up to neutron stars.

Over the last decade in relativistic heavy-ion collisions, the modification of hard QCD jets due to their passage through the Quark Gluon Plasma (QGP) has turned from a discovery to a precision tool to study the internal structure of the QGP. We will focus on a variety of issues related to the use of this tool as a probe of the plasma. This will be followed by a brief discussion of some of the differing approaches to this problem and new insights being extracted from current measurements. With the ever growing amount and variety of data, and the increasing sophistication of theoretical techniques, the study of jet modification is morphing into a multi-disciplinary enterprise involving computer scientists and statisticians working in collaboration with heavy-ion theorists and experimentalists. We will conclude with a preview of these exciting upcoming developments and their potential to resolve the structure and dynamics of the QGP.

An overview is given on our recent extreme precision mass measurements on single cooled ions stored in Penning traps. Mass measurements provide crucial information for atomic, nuclear and neutrino physics as well as for testing fundamental symmetries. For example, the most stringent test of CPT symmetry in the baryonic sector has been performed by mass comparison of the antiproton with H-. Furthermore, we improved the knowledge of the electron atomic mass by a factor of 13. Together with our newly determined proton mass, this most precise electron-to-proton mass ratio influences the Rydberg constant.

Type I X-Ray Bursts: Experimental Methods and Astrophysical Modeling

Neutron producing reactions serve an important role in a multitude of astrophysical scenarios; from (α,n) reactions that fuel stellar nucleosynthesis in asymptotic giant branch stars, to single nucleon transfer reactions which probe single-particle states important to the r-process. Experimental efforts requiring neutron detection of astrophysically relevant reactions can be broken down in to two general categories: direct and indirect approaches. Current and future efforts are focused on measurements at deep underground laboratories in order to obtain the necessary reduction in environmental background. This has primarily been driven by a lack of neutron spectroscopy. Indirect approaches are primarily focused on reactions with radioactive ion beams where direct measurements are not feasible. These are often performed in inverse kinematics where low beam intensities and reaction kinematics make these measurements difficult. In this talk, experimental challenges and opportunities in neutron detection for both direct and indirect approaches will be discussed. Experimental techniques such as neutron spectrum unfolding with deuterated scintillators, quasi-spectroscopic measurements, and new detection materials will also be discussed.

Committee: Dave Morrissey(Chairperson), Sean Liddick, Paul Mantica, Michael Thoennessen A technique called projectile fragmentation has been used to produce rare and short-lived nuclei for study at a variety of isotope production beam facilities such as the National Superconducting Cyclotron Laboratory (NSCL). Relatively few exclusive measurements of the final fragments from projectile fragmentation reactions have been made, even though they can provide more insight into the production process by comparing the measurements to models that simulate collisions and reactions on nuclei. The present work examines exclusive measurements of neutrons in coincidence with isotopically identified products. Two intermediate-energy (55.5 MeV/u) projectile fragmentation beams of 30S and 40S nuclei were produced and reacted with beryllium targets at the NSCL to produce a wide range of projectile fragments. Resulting heavy residue fragments were measured with the Sweeper magnet charged particle detectors and neutrons were detected in coincidence using the Modular Neutron Array and Large-area multi-Institutional Scintillator Array (MoNA LISA) detectors. A broad range of fragments was identified in each reaction for elements with Z = 6-11. To explore the projectile fragmentation process, the present results were compared to predictions from two very different nuclear reaction models. The hit multiplicity distributions observed in MoNA LISA for the summed elemental and individual isotopic products were compared to the two simulations. The first calculational approach involved the Liège Intranuclear Cascade (INCL++) model, a microscopic model and Monte Carlo based code that considers the reaction as a two-step process with collisions between individual nucleons followed by a de-excitation process of the intermediate and highly excited residue. The second approach involved the Constrained Molecular Dynamics (CoMD) model, a more macroscopic quantum mechanical model that follows the dynamical evolution of nuclear matter using the nuclear equation of state with three options for the symmetry energy term. The output of the CoMD model was coupled to GEMINI++ to de-excite any remaining hot fragments. Results from both simulations were passed through the GEANT4 code to model the neutron response of MoNA LISA to produce simulated hit multiplicity distributions that could be compared to the experimental hit multiplicity distributions. The majority of identified fragments were measured in coincidence with no neutron hits. Because the INCL++ model prediction better matched the proportion of fragments with zero hits and the CoMD + GEMINI++ simulations under-predicted the proportion of fragments produced with zero hits, INCL++ did an overall better job at predicting the observed hit multiplicity proportions. However, INCL++ failed to generate enough events with higher hit counts in MoNA LISA. Furthermore, the three CoMD + GEMINI++ symmetry energy options did not appear to produce noticeably different hit multiplicity distributions and no constraint on the symmetry energy could be made with this experimental data set. The distributions of precursor fragments in both the INCL++ and CoMD models were also examined. Many of the precursor fragments contained more nucleons than the projectile, indicating that both models predict that the projectile picks up nucleons from the target during the initial encounter. This prediction differs from common descriptions of these reactions.

Computing the ground state energy of quantum many-particle systems is of fundamental importance in a variety of fields, including chemistry, physics and materials science, amongst others. However, the complexity of such quantum mechanical computations grows rapidly with the number of particles, which limits scientific progress. Machine learning algorithms do not simulate the physical system, but instead, estimate solutions by interpolating values provided by a training set of known examples. However, precise interpolations may require a number of examples that is exponential in the system dimension and are thus intractable. Tractable algorithms compute interpolations in low dimensional approximation spaces, which leverage the underlying physical properties of the system. In this talk I will give an overview of machine learning algorithms for computing the ground state energy of quantum many-particle systems, describing the core principles of such algorithms and illustrating the common themes that emerge. I will then present in more detail our approach to the problem, which is based on a type of multiscale, multilayer convolutional neural network, called a wavelet scattering transform. Through a cascade of multiscale wavelet transforms and nonlinearities, the scattering transform encodes the appropriate invariants and regularity properties of the physical system. Wavelet scattering regressions, computed over databases of organic molecules and amorphous materials, achieve errors on the order of quantum mechanical simulations, but at a fraction of the computational cost.

Despite a difference in size of eighteen orders of magnitude, understanding the spatial distribution of neutrons in atomic nuclei with large neutron excess has a profound impact on the structure and composition of neutron stars. In particular, the development of a neutron skin in neutron-rich nuclei such as 208Pb has important consequences in constraining effective nuclear models that aim to describe within a single unified framework the dynamics of both atomic nuclei and neutron stars. Indeed, two of the main science drivers of the Facility for Rare Isotope Beams (FRIB) are the study of the heaviest of elements and the production of exotic nuclei with very thick neutron skins. Similarly, the upcoming parity-violating electron scattering measurements at Jefferson National Accelerator Facility (JLAB) aims to measure neutron skins with enough precisions that shall be instrumental in supplying critical calibrating anchors to the FRIB measurements. On the other hand, one of the NASA’s Programs, the Neutron star Interior Composition Explorer (NICER) is dedicated to studying the exotic structure and composition of neutron stars. Very recently a very powerful new player has entered the game. The first direct detection of gravitational waves from a binary neutron star merger (GW170817) by the LIGO-Virgo collaboration has opened the new era of multimessenger astronomy. Since the gravitational-wave signal is sensitive to the underlying EOS, in particular, limits on the tidal deformability inferred from the observation translate into constraints on the bulk properties of the EOS of neutron-rich matter. In this talk, I discuss our recent work in this area, where we employed a set of realistic models of the equation of state (EOS) and confronted our predictions with the measured tidal deformability from the BNS merger. In particular, given the sensitivity of the neutron-skin thickness of 208Pb to the pressure of neutron-rich matter, we inferred the density slope of the symmetry energy of L ≲ 80 MeV, a corresponding upper limit on the neutron skin thickness of Rskin ≲ 0.25 fm, and a neutron star radius of R1.4 ≲ 14 km.

Simulations of complex many-body quantum phenomena present a formidable computational challenge. Quantum computing holds promise to drastically improve our simulations capabilities for many-body systems across all scientific domains. We discuss recent progress and challenges in quantum simulations of light nuclei (the deuteron 2H, the triton 3H, 3He, and the alpha particle 4He ) and a prototypical quantum field theory---the Schwinger model---on a multitude of quantum hardware ranging from superconducting circuits and trapped ions to photonics. Our results illustrate the potential of quantum computers to augment classical computations in bridging the scales from quarks to nuclei.

In this talk I will discuss results from the seven papers given below and their interconnections. They are based upon determining the parameters used in energy-density-functional calculations from binding energies, root-mean-square charge radii, and nucleon separation energies, of magic nuclei including 48Ni and 100Sn. The results are used to make extrapolations to nuclear matter equations of state (EOS) including the symmetry energy and the neutron matter EOS. I will discuss the connections of these EOS to the neutron skin, and the differences in the charge radii of mirror nuclei. I will review some recent related work including those from neutron-star mergers.

Fry Fang, NSCL- Progress Towards the Single Atom Microscope - Growing Thin Films of Noble Gases of SAM Bingnan Lu, NSCL- Ab initio nuclear thermodynamics

Los Alamos National Laboratory (LANL) has a long history of making significant contributions in accelerator science and technology through on-going projects that support National Security. Many of these contributions have impacted accelerator designs world-wide for high-power accelerator applications and Free-Electron Lasers. Projects have ranged from recent small-scale application of accelerators in space to the design of the 1-MW Spallation Neutron Source at Oak Ridge. LANL also operates two large-scale accelerator facilities: an 800-MeV proton linac at the Los Alamos Neutron Science Facility (LANSCE) and two 20-MeV, multi-kilo-ampere, induction linacs at the Dual-Axis Radiographic Hydrodynamic Test Facility (DARHT). A brief overview of LANL accelerator science and technology contributions and our facilities will be presented, followed by a discussion of current accelerator projects that support various LANL missions. Opportunities for accelerator science and engineering students and early-career staff will also be presented. This work is supported by the United States Department of Energy, National Nuclear Security Agency, under contract DE-AC52-06NA25396.

Marginally bound or unbound quantum systems exhibit generic behaviors stemming from the presence of close-lying reaction and decay channels, and therefore they must be treated in the open quantum system framework. In nuclear physics, studies of exotic nuclei far from the valley of beta stability have revealed phenomena characteristic of open quantum systems, and are at the origin of a new paradigm in low-energy nuclear physics toward the unification of nuclear structure and reactions. In this talk, I will present current theoretical strategies in this area in the context of science drivers of the Facility for Rare Isotope Beams.

Sensitivity studies of the late stages of stellar core-collapse with respect to electron-capture rates indicate the importance of a region of nuclei near the N = 50 shell closure, just above doubly magic 78Ni. In the present work, it has been demonstrated that uncertainties in key characteristics of the evolution, such as the lepton fraction, electron fraction, entropy, stellar density, and in-fall velocity are about 50% due to uncertainties in the electron-capture rates on nuclei in this region, although thousands of nuclei are included in the simulations. The present electron-capture rate estimates used for the nuclei in this region of interest are primarily based on a simple approximation, and it is shown that the estimated rates are likely overestimated by an order of magnitude or more. More accurate microscopic theoretical models are required to obtain Gamow-Teller strength distributions, upon which electron-capture rates are based. The development of these models and the benchmarking of such calculations rely on data from charge-exchange experiments at intermediate energies. Experiments using the (t,3He) reaction on 86Kr and 88Sr, recently performed at the NSCL, offer an interesting comparison between experimental Gamow-Teller distributions and those yielded from theoretical models, and highlight the further work needed to provide accurate nuclear physics inputs to astrophysical simulations.

Nuclear reactions are an essential tool for probing the structure of nuclei. One class of reactions known as ‘transfer reactions’ are useful in determining spins, parities, and spectroscopic factors of single-particle levels. As a further example, deuteron-induced transfer reactions on unstable nuclei have been used to infer cross sections for direct neutron capture. Since the observables measured in reaction experiments are differential cross sections, extracting structure properties requires a robust reaction theory. In light of reaction measurements taking place in rare isotope facilities around the world and in anticipation of a large influx of data from FRIB, reliable reaction theories that are suitable for exotic nuclei are needed. Using the example of (d, p) reactions, I will illustrate the importance of a dependable reaction theory in translating experimental measurements into structure information. The (d, p) reactions can be viewed as a three-body problem which is described exactly by the Faddeev equations. I will discuss the current status of this theoretical approach and potential applications to a variety of reactions in-volving radioactive beams.

The standard model's most precise prediction -- of the size of the electron magnetic moment -- is tested using a single electron suspended by itself for months at a time in a tabletop-sized measurement. Our ACME team has just reported a new measurement of the electron's other moment -- its electric dipole moment -- a very different tabletop measurement. The standard model and proposed alternatives/additions differ sharply in their predictions of the size of this moment.

Nuclei are unique quantum many-body systems which can exhibit a very rich variety of behaviors. While historically the many-body methods have been developed in order to tackle specific mass regions or physical phenomena, one of the goals of modern nuclear theory is to connect and unify these methods in order to ultimately reach a universal, precise and predictive description of nuclei. In my talk I will discuss two approaches that follow this direction: 1) The self-consistent multiparticle-multihole configuration mixing method, at the crossroads between shell models and mean-field methods, considers the nuclear wave function as a superposition of Slater determinants built on an optimized single-particle basis that is solution of a generalized mean-field equation. I will present first applications of this approach to ground and excited properties of light and sd-shell nuclei; and will discuss future plans in the context of FRIB physics. 2) The relativistic nuclear field theory starts from a relativistic mean-field approximation and builds inter-nucleon correlations that emerge from the coupling between single nucleons and collective vibrations of the nucleus. I will show recent applications of this approach to charge-exchange modes and weak-interaction processes in mid-mass and heavy nuclei that will be investigated by FRIB.

Nuclear reactions are key inputs to stellar evolution, nucleosynthesis, and other astrophysical models. Especially in hot environments, the structure of the reacting nuclides impacts both reaction rates and, in the case of weak interactions, the resulting neutrino spectra. I will present some of my recent work in this area, which includes the impact of nuclear structure on expected neutrino signals from nearby pre-supernova stars. It may be possible to detect neutrinos from nearby pre-supernova stars. Leading up to core collapse, beginning around silicon burning, nuclei become dominant producers of neutrinos, particularly at higher neutrino energy, so a systematic study of nuclear neutrino spectra is desirable. My collaborators and I have done such a study using shell model calculations and a modified Brink-Axel hypothesis in sd-shell nuclei which includes neutrinos produced by charged lepton capture, charged lepton emission, and neutral current nuclear deexcitation. Previous authors have tabulated the rates of charged current nuclear weak interactions in astrophysical conditions, but the present work expands on this not only by providing neutrino energy spectra, but also by including the heretofore untabulated neutral current deexcitation neutrino pairs. Extension of the study to heavier mass regions using state-of-the-art shell models has been planned and is currently in the initial phases. Time permitting, I will also present some work on the behavior of nuclear isomers.

The first detection of gravitational waves from a merging double neutron star (DNS) binary challenged our understanding of evolution of its potential progenitor systems, implying a much higher rate of DNS coalescences in the local Universe than predicted on theoretical grounds. Those theoretical estimates for the isolated binary evolution scenario are usually based on results from population synthesis calculations. The wide range of values for the calculated merger rates often quoted in population synthesis studies reflects our limited knowledge of the details of evolution and interactions of massive stars in binaries, which one can hope to improve by confrontation with the observational limits. In the era of gravitational wave observations this becomes a promising tool to learn about the formation of merging systems. However, this comparison is far from being straightforward. Binaries that merge within the local Universe originate from progenitor systems that formed at different redshifts and in various environments. The efficiency of formation of double compact objects is highly sensitive to metallicity of the star formation. Therefore, to confront the theoretical estimates with observational limits resulting from gravitational waves observations one has to account for the formation and evolution of progenitor stars in chemically evolving Universe. This introduces another layer of uncertainty to those calculations that needs to be better understood.

To decisily upgrade the luminosity of the LHC, and increase its Physics reach, the High Luminosity LHC project is opening a new territory, developing accelerator magnets in the 12 tesla range based on advanced Nb3Sn technology and long superconducting links rated for 100 kA with novel MgB2 superconductors. The talk will discuss the status of these new technologies for HL-LHC, now at the verge of entering into production, as well as the studies under way for the post-LHC Hadron Collider. In particular, for the FCC more pushed Nb3Sn magnets, designed for 16 T, are under design and the first basic R&D on HTS (High Temperature Superconductors) accelerator magnets has started in order to explore the 20 T frontier.

The recent LIGO/VIRGO detection of gravitational radiation fromGW170817 bears the clear signature of a binary neutron star merger and has validated a number of theoretical predictions. High-energy radiation in the form of a short gamma-ray burst was observed 1.7 s following the merger, and an extended optical/infrared afterglow lasting weeks was observed by dozens of observatories. Short gamma-ray bursts had been thought to be produced by mergers, and the afterglow is the predicted signal of radioactive decays from decompressing neutron-rich matter catastrophically ejected from the merging stars. The afterglow provided solid evidence that neutron star mergers are a major, if not primary, source of the r-process nuclei, about half of all nuclei heavier than iron formed from the rapid capture of neutrons. Although this idea was proposed nearly 45 years ago, it was largely ignored in favor of a supernova mechanism. Over the last decade, however, evidence has been accumulating from geochemical and astronomical observations that supernovae are not the primary source of the r-process.GW170817 may have finally settled this question, which has been one of the thorniest problems in nuclear physics and astrophysics. This talk presents my personal perspective of this paradigm shift.

Committee: Daniel Bazin (Chairperson), Artemis Spyrou, Christopher Wrede, Remco Zegers

Observations of quasi-persistent X-ray transients, neutron stars which exhibit alternate phases of accretion and cooling, yield information about the interior structure of a neutron star. During quiescence, the X-ray profile and luminosity depend on the thermal evolution and structure of the neutron star. The electron degeneracy in the crust allows electron captures to occur on the rp-process ashes, transforming them into increasingly neutron-rich species as the depth of the ash increases. At the boundaries between species, Urca cycling can occur, leading to intense neutrino cooling. The strength of this cooling depends significantly on the b decay transition strength between ground states of these neutron-rich nuclei. A recent experimental effort to precisely quantify the ground state to ground state transition strength of the potentially strong cooler 61V will be presented, along with prospects for further experimental work.