Bulletin of the American Physical Society
6th Joint Meeting of the APS Division of Nuclear Physics and the Physical Society of Japan
Sunday–Friday, November 26–December 1 2023; Hawaii, the Big Island
Session E09: Nuclear Astrophysics III |
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Chair: Andrew Ratkiewicz, Lawrence Livermore National Laboratory Room: Hilton Waikoloa Village Kohala 2 |
Wednesday, November 29, 2023 7:00PM - 7:15PM |
E09.00001: Progress Towards a Single Atom Miscroscope (SAM) for Nuclear Astrophysics Karina Martirosova, Roberto Hernandez, Erin E White, Ben Mellon, Nick Koester, Jaideep T Singh Development of a detector that is efficient, selective and sensitive at the single atom level is necessary for the measurement of low yield nuclear reactions that are relevant for nuclear astrophysics. These low yield reactions may be due to either very low cross-sections or low beam intensity. We are developing the single atom microscope (SAM) technique to study the 22Ne(α, n)25 Mg reaction, which is an important source of neutrons for the s-process. The s-process in stars forms approximately half the atomic nuclei heavier than iron through neutron capture. This particular reaction is challenging to measure as it requires low background and high selectivity to distinguish the products from the intense unreacted beam. Therefore, as a proof-of-principle measurement, we are aiming to study the 84Kr(p, γ)85Rb reaction first, which plays a role in the p-process in stars. The SAM technique works by first capturing reaction products in a cryogenically frozen noble gas film and then detecting product atoms by laser induced fluorescence via a CCD camera. We will report on our progress towards demonstrating single atom sensitivity, which is feasible due to the large shift between the excitation and emission wavelengths.This work is supported by U.S. National Science Foundation under grant number #1654610 and is based upon wok supported by the Department of Energy National Nuclear Security Administration through the Nuclear Science and Security Consortium under Award Number DE-NA0003996. |
Wednesday, November 29, 2023 7:15PM - 7:30PM |
E09.00002: Observed reduction of α-decay rate under compression and correlation to decay Q-value Amlan Ray, Arindam K Sikdar, Joydip Nandi, Jagannath Datta, Jaykumar D Patel, Riya Baidya, Parnika Das, Deepak Pandit The observation of uranium in the extremely metal-poor stars and Uranium/Thorium cosmochronometry play important roles to date r-process events in early Galaxy [1]. So, it is important to study possible changes of α-decay rate under compression inside the stars [2]. Lattice compression of α-emitting radioactive atom is a way to study the effect of pressure. |
Wednesday, November 29, 2023 7:30PM - 7:45PM |
E09.00003: 56Ni Problem in Core-collapse Supernova Explosion RYO SAWADA, Yudai Suwa Details of the core-collapse supernova (CCSN) explosion mechanism still need to be fully understood. There is an increasing number of successful examples of reproducing explosions in multidimensional hydrodynamic simulations [1], but subsequent studies pointed out that the growth rates of the explosion energy of these simulations are insufficient to produce enough 56Ni to match observations [2]. This issue is known as the `56Ni problem' in CCSNe. |
Wednesday, November 29, 2023 7:45PM - 8:00PM |
E09.00004: Constraining Nuclear Models and Equation of State with Parity-violating Asymmetry of 208Pb and 48Ca Tianqi Zhao, Zidu Lin, Andrew Steiner, Madappa Prakash, Bharat Kumar Neutron skin of 48Ca and 208Pb have been known to provide important information about the symmetry energy of nuclear matter. Previous skin measurements involving strong integration probes might be subject to various systematic errors. Purely electro-weak probes such as parity-violating asymmetry of 48Ca (CREX) and 208Pb (PREX) in elastic electron scattering are particularly valuable. We generate a few hundred thousand energy density functional and calculate finite nuclear properties, infinite nuclear matter properties as well as neutron star properties. Our joint analysis of PREX and CREX data flavor energy density functional with a large bulk symmetry energy Sv and a small slope L, which is in 2-sigma (95%) tension with nuclei masses and charge radii. This tension leads to a strong constraint on symmetry energy slope L=42+15−17 MeV. The posterior distribution is dominated by CREX data since CREX ruled out large L while PREX likelihood has a big tail which is compatible with small L. Joint analyses with astronomical constraints including maximum mass, tidal deformability, and radius observation slightly tighten the lower bound L=43+15−11 MeV. Furthermore, we found the result agree nicely with previous neutron skin experiment, dipole probabilities as well as ab-initial calculation. |
Wednesday, November 29, 2023 8:00PM - 8:15PM |
E09.00005: High Resolution Study of 40Ca to Constrain Globular Cluster NGC 2419 William C Fox, Richard Longland, Caleb Marshall, Federico E Portillo Chaves Globular clusters exhibit abundance correlations between light-element pairs in their low-mass stars. These correlations result from mixing with the pollution of older stars in the cluster. The Mg-K anticorrelation among red giants in the cluster NGC 2419 is an intriguing example due to its strong K enrichment. The enrichment mechanism stems from hydrogen burning in the polluter stars at temperatures between 80–260 MK. However, the key potassium-destroying reaction, 39K(p, γ)40Ca, has a large reaction rate uncertainty at these temperatures. We significantly constrain its reaction rate with a high resolution 39K(3He, d)40Ca study using the Enge Split-Pole Spectrograph at the Triangle Universities Nuclear Laboratory. We resolve the 154 keV resonance in 39K+p for the first time, leading to an increase in the previously calculated rate by up to a factor of 13 and a reduction in its 1σ width by up to a factor of 42. Using reaction network calculations, we demonstrate the effect this new rate has on the T-ρ conditions that reproduce the observed Mg-K anticorrelation. |
Wednesday, November 29, 2023 8:15PM - 8:30PM |
E09.00006: DMRadio: Overview, Status Updates, and Plans Alexander G Droster The QCD axion is a promising dark matter candidate whose discovery would also solve the Strong CP problem of particle physics. The DMRadio suite of experiments, which consists of DMRadio-50L, DMRadio-m3, and DMRadio-GUT, are designed to be sensitive to QCD axions in the peV to ueV mass range. Axions in this mass range may be produced in the measured dark matter abundance in the early universe if Peccei-Quinn symmetry breaking occurred prior to inflation. However, state-of-the-art searches for axions using resonant cavities cannot probe axions in this mass range because the axion's Compton wavelength is very large compared to the size of the detector. Therefore, the DMRadio suite of experiments uses lumped-element LC resonators to decouple the resonance frequency from the physical size of the detector. DMRadio-50L probes axions in the 100 kHz to 5 MHz range and is nearing construction completion. DMRadio-m3 is sensitive to the DFSZ axion model within 30 MHz-200 MHz, is sensitive to the KSVZ axion model within 10 MHz-30 MHz, and its design is nearing completion. Here we present an overview of the design and status updates of DMRadio-50L and DMRadio-m3, and briefly describe the next-generation experiment DMRadio-GUT. |
Wednesday, November 29, 2023 8:30PM - 8:45PM |
E09.00007: Study of neutron-induced charged particle reactions relevant to the synthesis of 40K in massive stars Panagiotis Gastis, Sean A Kuvin, Hye Young Lee, Kenneth G Hanselman, Toshihiko Kawano, Nikolaos Dimitrakopoulos, Georgios Perdikakis 40K is found among other naturally occurring radionuclides to be primarily responsible for the radiogenic heating of terrestrial-type planets. Radiogenic heating, i.e., heating produced by exothermic decays of long-lived radioactive nuclei, has implications in the evolution of habitable environments in extrasolar planetary systems and its study has been intensified over the last decade. State-of-the-art methods of modeling the radiogenic heating in exoplanets currently rely on Galactic Chemical Evolution models for predicting the concertation of 40K in the system; within this context, the rate of nuclear reactions relevant to the synthesis of 40K in stellar environments can play an important role. 40K is formed is massive stars during stellar evolution while its final abundance is particularly sensitive to the 40K(n,p)40Ar and 40K(n,α)37Cl reactions. In this presentation, results from the first direct measurement of 40K(n,p)40Ar and 40K(n,α)37Cl reaction cross-sections with fast neutrons will be discussed. The measurements took place at the Los Alamos Neutron Science Center (LANSCE) using the Low-Energy (n,Z) (LENZ) detector system. Based on the new data, improved stellar reaction rates were extracted that will enhance the accuracy of stellar yield calculations for 40K. |
Wednesday, November 29, 2023 8:45PM - 9:00PM |
E09.00008: Superheavy Element in Kilonovae Erika M Holmbeck, Jennifer Barnes, Kelsey A Lund, Trevor M Sprouse, Gail C McLaughlin, Matthew R Mumpower With LIGO-Virgo-KAGRA in its fourth observing run, a new opportunity to search for electromagnetic counterparts of compact object mergers has also begun. The light curves and spectra from the first "kilonova" associated with a binary neutron star binary (NSM) suggests that these sites are hosts of the rapid neutron capture (r) process. However, it is unknown just how robust elemental production can be in mergers. Identifying signposts of the production of particular nuclei is critical for fully understanding merger-driven heavy-element synthesis. In this study, we investigate the properties of very neutron rich nuclei for which superheavy elements (Z≧104) can be produced in NSMs and whether they can similarly imprint a unique signature on kilonova light-curve evolution. This talk will discuss how superheavy-element production may be identified in NSMs and possibly supply the first evidence of superheavy element synthesis in nature. |
Wednesday, November 29, 2023 9:00PM - 9:15PM |
E09.00009: Low energy Mg + Ne fusion studies in applications of pycnuclear burning in accreting neutron stars Javier Rufino, Tan Ahn, Patrick O'Malley, Jaspreet S Randhawa, James J Kolata, Thomas L Bailey, Scott R Carmichael, Kevin Lee, William S Porter, William W von Seeger, Joseph Henning In the crust of an accreting neutron star, there are many kinds of nuclear reactions that can occur such as neutron emission, electron capture, and pycnonuclear burning. And of those reactions, current models predict that pycnonuclear burning contributes the most to crustal heating, specifically in the neutron-rich mass regions of Mg + Mg, Ne + Ne, and Mg + Ne fusion. However, there is a lack of experimental data in the neutron-rich and stable mass regions of these fusion reactions, and as a result, calculated cross-sections using different models can differ by many orders of magnitude at the energies of interest. To constrain a portion of these fusion cross-sections, experiments in the stable mass regions of Mg and Ne have been performed in the Nuclear Science Lab at the University of Notre Dame using the FN Tandem Accelerator and the ND-Cube, an active-target time projection chamber. Results of the 24Mg + 20Ne and 26Mg + 20Ne fusion experiments will be presented, in addition to an outlook for experiments in neutron-rich mass regions of Mg + Ne fusion at user facilities, and the development of a simulation program to perform grid search beam parameter optimization for online analysis of future experiments. |
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