PaperPanorama
FAQ

Nuclear Theory·nucl-th

Tuesday·March 26, 2024

16 papers—7 primary·9 cross-listed

All16Primary7Cross-lists9
  1. 01

    Exploring the Big Bang with femtoscopy

    Mate Csanad🇭🇺

    Exploring the fundamental constituents of the matter around us and in the Universe, as well as their interactions, is among the premier goals of physics. Investigating ultrarelativistic collisions in particle accelerators has delivered answers to these questions many times in the past decades. In this paper we focus on the research aimed at recreating the matter that filled the Universe in the first microsecond after the Big Bang -- but this time in collisions of heavy ions. In particular we discuss the technique called femtoscopy, which provides us a tool to understand the space-time structure of particle creation in heavy-ion collisions. We utilize Levy-stable distributions to investigate this structure and explore its dependence on particle momentum and collision energy.

    nucl-thnucl-exEur.Rev.(2024)·0 citations
  2. 02

    Heaven and Earth: Nuclear Astrophysics after GW170817

    J. Piekarewicz

    The historical detection of gravitational waves from the binary neutron star merger GW170817 is providing fundamental new insights into the astrophysical site for the creation of the heaviest elements in the cosmos and on the equation of state of neutron-rich matter. Shortly after this historical detection, electromagnetic observations of neutron stars together with measurements of the properties of neutron-rich nuclei at terrestrial facilities have placed additional constraints on the dynamics of neutron-rich matter. It is this unique synergy between heaven and earth that is the focus of this article.

    nucl-thastro-ph.SRnucl-exEPJ Web Conf.(2024)·2 citations
  3. 03

    Illuminating Systematic Trends in Nuclear Data with Generative Machine Learning Models

    Jordan M. R. Fox · Kyle A. Wendt

    We introduce a novel method for studying systematic trends in nuclear reaction data using generative adversarial networks. Libraries of nuclear cross section evaluations exhibit intricate systematic trends across the nuclear landscape, and predictive models capable of reproducing and analyzing these trends are valuable for many applications. We have developed a predictive model using deep generative adversarial networks to learn trends from the inelastic neutron scattering channel of TENDL for even-even nuclei. The system predicts cross sections based on adding/subtracting particles to/from the target nucleus. It can thus help identify cross sections that break from expected trends and predict beyond the limit of current experiments. Our model can produce good predictions for cross section curves for many nuclides, and it is most robust near the line of stability. We also create an ensemble of predictions to leverage different correlations and estimate model uncertainty. This research marks an important first step in computer generation of nuclear cross-section libraries.

    nucl-thphysics.comp-ph1 citation
  4. 04

    Effect of Light Nuclei on Chemical Freeze-out Parameters at RHIC Energies

    Ning Yu · Zuman Zhang · Hongge Xu · Minxuan Song

    In this study, the chemical freeze-out of hadrons, including light-and strange-flavor particles and light nuclei, produced in Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC), was investigated. Using the thermal-FIST thermodynamic statistical model, we analyzed various particle sets: those inclusive of light nuclei, those exclusive to light nuclei, and those solely comprising light nuclei. We determined the chemical freeze-out parameters at 7.7--200 GeV and four different centralities. A significant finding was the decrease in the chemical freeze-out temperature with light nuclei inclusion, with an even more pronounced reduction when considering light nuclei yields exclusively. This suggests that light nuclei formation occurs at a later stage in the system's evolution at RHIC energies. We present parameterized formulas that describe the energy dependence of and the baryon chemical potential for three distinct particle sets in central Au+Au collisions at RHIC energies. Our results reveal at least three distinct at RHIC energies correspond to different freeze-out hypersurfaces: a light-flavor freeze-out temperature of = 150.26 MeV, a strange-flavor freeze-out temperature = 165.12.7 MeV, and a light-nuclei freeze-out temperature = 141.71.4 MeV. Notably, at the Large Hadron Collider (LHC) Pb+Pb 2.76 TeV, the expected lower freeze-out temperature for light nuclei was not observed; instead, the for light nuclei was found to be approximately 10 MeV higher than that for light-flavor hadrons.

    nucl-thhep-phnucl-exNucl.Sci.Tech.(2025)·3 citations
  5. 05

    Limits on an improved action for contact effective field theory in two-body systems

    L. Contessi🇫🇷 · M. Pavon Valderrama🇨🇳 · U. van Kolck🇮🇹

    We consider a possible resummation of subleading effects in two-body systems with a large scattering length as described by a short-range effective field theory (EFT). In particular, we investigate the consequences of a resummation of part of the range corrections. Explicit calculations of the two-body phase shifts and charge form factor indicate that, except for extreme choices, resummations do not alter the convergence of the EFT expansion and are often beneficial at lowest orders. We have considered the expansion when the regulator cutoff is removed as well as when it is finite, and find that the cutoff is not an important factor for resummations. Our results connect with other works where the partial resummation is induced by potentials with finite cutoffs or interaction ranges.

    nucl-thcond-mat.quant-gasPLB(2024)·13 citations
  6. 06

    A neural network approach for two-body systems with spin and isospin degrees of freedom

    Chuanxin Wang · Tomoya Naito · Jian Li · Haozhao Liang

    We propose an enhanced machine learning method to calculate the ground state of two-body systems. By extending the original method [Naito, Naito, and Hashimoto, Phys. Rev. Research 5, 033189 (2023)], the present method enables consideration of the spin and isospin degrees of freedom by employing a non-fully connected deep neural network and the unsupervised machine learning technique. The validity of this method is verified by calculating the unique bound state of the deuteron.

    nucl-thphysics.comp-phquant-phNucl.Sci.Tech.(2026)·9 citations
  7. 07

    Tuned electron-nucleus resonance as a tool of producing the 229mTh isomer

    F. F. Karpeshin

    The possibility of refining the energy of the 8.36-eV 229mTh nuclear isomer -- the most likely candidate for the role of a nuclear frequency standard -- by means of resonant optical pumping is discussed. Attention is focused on considering the broadening of the resonance in order to reduce scanning time. The two-photon method proposed exploits the radical broadening of the isomer line due to mixing with the electron transition. This is not burdened with the cross-section reduction, in contrast with internal-conversion-based resonance broadening or intended extra-broadening of the spectral line of a pumping laser. In the case under consideration, according to the calculations, it turns out to be two orders of magnitude more efficient. It is applicable to both ionized and neutral thorium atoms. Realization of the method supposes excitation of the both nucleus and electron shell in the final state.

    nucl-thFizika(2024)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE