Nuclear Theory·nucl-th

Monday·March 10, 2025

8 papers—4 primary·4 cross-listed

01
[Submitted on 7 Mar 2025]
Mirror-skin thickness: a possible observable sensitive to the charge symmetry breaking energy density functional
Tomoya Naito · Yuto Hijikata · Juzo Zenihiro · Gianluca Colò · Hiroyuki Sagawa
We propose a new observable, named the mirror-skin thickness, in order to extract the strength of the charge symmetry breaking (CSB) term in an energy density functional (EDF). The mirror-skin thickness of $N = 20$ isotones and $Z = 20$ isotopes is studied by using Hartree-Fock-Bogoliubov (HFB) calculations with various Skyrme EDFs and adding CSB and charge independence breaking (CIB) terms. It is shown that the mirror-skin thickness is sensitive only to the CSB EDF, but hardly depends on either the isospin symmetric part of the nuclear EDF or the CIB term. Therefore, this observable can be used to extract the magnitude of the CSB term in the EDF quantitatively, either from experimental data or ab initio calculations. We have studied the accuracy in the mirror-skin thickness that is needed to extract sensible information. Our study may also help to understand the inconsistency between the strength of the phenomenological CSB and that extracted from ab initio calculations [Naito et al. Nuovo. Cim. C 47, 52 (2024)]. Among possible mirror pairs for experimental study, we propose the mirror-skin thickness between $^{42} Ca$ and $^{42} Ti$ , which could be accessed in future experiments in RIBF and/or FRIB.
Comments:
14 pages, 13 figures, 2 tables
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2503.05147 [pdf]
EPJA(2025)·3 citations
02
[Submitted on 7 Mar 2025]
Electromagnetic emission from strongly interacting hadronic and partonic matter created in heavy-ion collisions
Adrian William Romero Jorge🇩🇪 · Taesoo Song🇩🇪 · Qi Zhou🇨🇳 · Elena Bratkovskaya🇩🇪
We investigate dilepton production in heavy-ion, proton-proton, and proton-nucleus collisions from low energies of 1 AGeV (SIS) to ultra-relativistic energies (LHC) using the Parton-Hadron-String Dynamics (PHSD) transport approach. PHSD is a microscopic, non-equilibrium approach that integrates hadronic and partonic degrees of freedom, providing a comprehensive description of relativistic heavy-ion collisions from initial nucleon-nucleon interactions to quark-gluon plasma (QGP) formation, hadronization, and final-state interactions. Key dilepton sources in PHSD include hadronic decays, bremsstrahlung, QGP radiation ( $q + q ˉ \to e^{+} e^{-}$ , \ $q + q ˉ \to g + e^{+} e^{-}$ , \ $q + g \to q + e^{+} e^{-}$ ), primary Drell-Yan production, and semileptonic decays of correlated charm and bottom pairs. PHSD well describes dilepton data from HADES, STAR, and ALICE experiments. We examine in-medium effects, such as the vector meson spectral function broadening, and present the excitation function for the dilepton "excess" in the invariant mass range $0.4 < M_{ee} < 0.75$ GeV/c $^{2}$ . For the first time we report on the baryon chemical potential $μ_{B}$ -dependence of the QGP radiation calculated on a basis of the Dynamical-Quasi-Particle Model (DQPM) in PHSD. The influence of $μ_{B}$ on the QGP yield grows at lower collision energies, where $μ_{B}$ becomes large, however, its impact on the total dilepton spectra is small due to the lowering of the QGP volume with decreasing energy. The excitation function of QGP dileptons, is presented versus correlated charm, confirming that the QGP radiation overshines charm contributions at $s ≃ 25 - 30$ GeV in central Au+Au collisions, providing access to thermal QGP dileptons at BES RHIC and FAIR.
Comments:
extended version (29 pages, 24 figures) to be published in Phys. Rev. C
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2503.05253 [pdf]
PRC(2025)·13 citations
03
[Submitted on 7 Mar 2025]
Calculation of low-energy scattering parameters using artificial oscillator trap
D.V.Fedorov · A.M.Pedersen
We introduce a recipe to estimate the low-energy scattering parameters of a quantum few-body system - scattering length, effective range, and shape parameter - by using only discrete state calculations. We place the system in an artificial oscillator trap of appropriate size and calculate the energies of the resulting discrete states close to the threshold of the system. The low-energy scattering parameters are then extracted - using a simple analytic formula - from the functional dependence of these energies upon the trap size. We first test the recipe against a simple model problem and then apply it to low-energy nucleon-nucleon scattering within the nuclear Model with Explicit Mesons in one sigma-meson approximation.
Comments:
Extra references added, a few sentences rephrased
Subjects:
Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2503.05295 [pdf]
Few Body Syst.(2025)·1 citation
04
[Submitted on 7 Mar 2025]
Mass fractions in stellar interior during presupernova evolution
Jameel-Un Nabi · Abdel Nasser Tawfik · Nada Ezzelarab · Ali Abas Khan
We assume nuclear statistical equilibrium (NSE) conditions and use Saha Equation to calculate mass fractions in stellar interior during presupernova evolution of massive stars. Our ensemble contains 728 nuclei. The distinguishing feature of our calculation is a state by state summation of nuclear level densities up to 10 MeV for all nuclei considered in our ensemble. This leads to a more realistic description of nuclear partition function which poses one of the largest uncertainties in the mass fraction calculations under conditions of NSE. The Coulomb correction term was taken into account for the calculation of ground state binding energies of the nucleons. Our calculated mass fractions are up to four orders of magnitude smaller than previous calculation. The current calculation could prove useful for study of stellar matter during presupernova phases of massive stars.
Comments:
14 Pages, 4 Table , 6 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2503.05517 [pdf]
Astrophys.Space Sci.(2016)·5 citations
05
[Submitted on 1 Mar 2025] (cross-list from physics.ins-det)
Development and Benchmarking of JANGOFETT: A Novel Geant4-Operated Fission Event Tracking Tool
Liam Walker · Jack Shire · Jacob Jaffe · Payton Sprando · Jack Olinger · Alexander Chemey
Experiments measuring fission observables encounter false coincidences arising from timing overlap of separate fission product decays. Simulations of both fission observables and particles in detector systems exist, but have not yet been combined to produce accurate event-by-event outputs in a time-dependent manner. Geant4 is a powerful simulation tool for nuclear physics studies, but it does not handle multiple initial particles in a single simulation instance, nor does it feature high fidelity fission sampling. JANGOFETT: A Novel Geant4-Operated Fission Event Tracking Tool has been developed to address this challenge. The tool utilizes simulated fission data from an external program in conjunction with Geant4, which has been modified to produce a single timeline of events over an entire simulated experiment. The physical accuracy of the simulated overlapping energy depositions within detectors has been verified via simulation of fission products from the spontaneous fission of 252Cf.
Comments:
21 pages, 6 figures
Subjects:
Instrumentation and Detectors (physics.ins-det); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2503.04791 [pdf]
Nucl.Instrum.Meth.A(2026)·0 citations
06
[Submitted on 6 Mar 2025] (cross-list from hep-ph)
Improved evaluation of the electroweak contribution to muon $g - 2$
Martin Hoferichter🇨🇭 · Jan Lüdtke🇦🇹 · Luca Naterop🇨🇭 · Massimiliano Procura🇦🇹 · Peter Stoffer🇨🇭
A precise evaluation of the electroweak contribution to the anomalous magnetic moment of the muon requires control over all aspects of the Standard Model, ranging from Higgs physics, over multi-loop computations for bosonic and (heavy-)fermion diagrams, to non-perturbative effects in the presence of light quarks. Currently, the dominant uncertainties arise from such hadronic effects in the vector-vector-axial-vector three-point function, an improved understanding of which has recently emerged in the context of hadronic light-by-light scattering. Profiting from these developments as well as new perturbative and non-perturbative input for the charm contribution, we obtain $a_{μ}^{EW} = 154.4 (4) \times 1 0^{- 11}$ .
Comments:
8 pages, 2 figures; journal version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2503.04883 [pdf]
PRL(2025)·45 citations
07
[Submitted on 7 Mar 2025] (cross-list from nucl-ex)
$t$ + $t$ cluster states in $^{6}$ He
W. H. Ma · D. Y. Tao · B. Zhou · J. S. Wang · Y. G. Ma · D. Q. Fang · W. B. He · Y. Y. Yang · J. B. Ma · S. L. Jin · P. Ma · J. X. Li and 12 other authors
The study of $t$ + $t$ cluster states in $^{6}$ He provides valuable insights into exotic nuclear structures and the behavior of fermionic cluster systems. This study shows rich cluster resonant state structures above the threshold, identified by experimental reconstruction and theoretical calculations. The excitation energy spectrum above the $t$ + $t$ threshold in $^{6}$ He is measured via the fragmentation excitation process during the breakup reaction of $^{9}$ Li on a $^{208}$ Pb target at an incident energy of 32.7 MeV/nucleon. The resonant states are reconstructed from the final state coincident particles $t$ + $t$ using the invariant mass method, while the non-resonant background is estimated using the event mixing method. Two states of energy level peaks at $13.9 \pm 0.3$ and $15.0 \pm 0.3$ MeV are observed. Microscopic cluster model calculations exploring the $t + t$ resonant states in $^{6} He$ yield theoretical energy spectra which are then compared with the current experimental results. The calculated reduced width amplitudes (RWA) of the $t + t$ channels further confirm the clustering structure of the identified $t + t$ resonant states.
Comments:
9 pages, 5 figures,1 table
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2503.05497 [pdf]
0 citations
08
[Submitted on 7 Mar 2025] (cross-list from hep-ph)
Systematic optimization of resonance parameters in a transport approach
Carl B. Rosenkvist🇩🇪 · Hannah Elfner🇩🇪
This study optimizes resonance parameters responsible for strangeness production in the SMASH (Simulating Many Accelerated Strongly-interacting Hadrons) transport model using a genetic algorithm. By fitting resonance parameters to experimental data on exclusive strangeness cross-sections at low energies, we significantly improve the model's accuracy, especially in pion-proton interactions. Our approach explores how machine learning tools can be used for precise resonance tuning in transport approaches.
Comments:
9 pages, 14 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2503.05504 [pdf]
PRC(2025)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE