Nuclear Theory·nucl-th

Thursday·October 10, 2024

15 papers—8 primary·7 cross-listed

01
[Submitted on 8 Oct 2024]
The Hypertriton Puzzle in Relativistic Heavy-Ion Collisions
Thomas Cohen🇺🇸 · Maneesha Pradeep🇺🇸
The yields of hadrons and light nuclei in relativistic collisions of heavy-nuclei at a center of mass energy of 2.6 TeV can be described remarkably well by a thermal distribution of an ideal gas of hadrons and light nuclei interacting only via the decay of resonances. Given the particularly small binding energy of hypertritons relative to the temperature describing the yields (about 156 MeV), one might naturally expect hypertrions to dissociate in medium, making the agreement of hypertriton yields with thermal predictions highly puzzling. The puzzle is compounded by the fact that small binding energy is associated with the large size of the hypertriton. This size is on a similar scale to the overall size of the fireball and much larger than the length scale over which temperatures in the fireball vary over phenomenologically relevant amounts. This paper quantifies the tension this effect causes and shows that it is sufficiently large to render the thermal model inconsistent: its natural assumptions are in conflict with its outputs. The possibility that hypertritons are formed at freeze out as compact objects, quark droplets, that subsequently evolve into hypertritons is considered as a way to resolve the puzzle. It is noted that beyond making the assumption that compact quark droplets form, additional detailed dynamical assumptions which have not been justified are needed to make the thermal model work. The issue of why, despite these issues, the hypertriton is well described by a simple statistical description at freeze out is unresolved. Resolving the hypertriton puzzle is important as it may clarify whether the phenomenological success of the simple thermal model for yields accurately reflects the simple picture of the underlying physics on which it is based.
Comments:
21 pages
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2410.05569 [pdf]
PRC(2025)·3 citations
02
[Submitted on 8 Oct 2024]
16O electroweak response functions from first principles
Bijaya Acharya🇺🇸 · Joanna E. Sobczyk🇩🇪 · Sonia Bacca🇩🇪 · Gaute Hagen🇺🇸 · Weiguang Jiang🇩🇪
We present calculations of various electroweak response functions for the 16O nucleus obtained using coupled-cluster theory in conjunction with the Lorentz integral transform method. We employ nuclear forces derived at next-to-leading order and next-to-next-to-leading order in chiral effective field theory and perform a Bayesian analysis to assess uncertainties. Our results are in good agreement with available electron-scattering data at q~ 326 MeV/c. Additionally, we provide several predictions for the weak response functions in the quasi-elastic peak region at q= 300 and 400 MeV/c, which are critical for long-baseline neutrino experiments.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2410.05962 [pdf]
PRL(2025)·20 citations
03
[Submitted on 8 Oct 2024]
White Dwarf Structure and Binary Inspiral Gravitational Waves from Quantum Hadrodynamics
Ling-Jun Guo🇨🇳 · Yao Ma🇨🇳 · Yong-Liang Ma🇨🇳 · Ruo-Xi Wu🇨🇳 · Yue-Liang Wu🇨🇳
White dwarfs, one of the compact objects in the universe, play a crucial role in astrophysical research and provide a platform for exploring nuclear physics. In this work, we extend the relativistic mean field approach by using a Walecka-type quantum hadrodynamics model to capture the intricate structure of white dwarfs. We calculate nuclear properties, Coulomb energy, and photon energy within white dwarfs in a unified framework. By carefully calibrating the model parameters to align with nuclear matter properties, we successfully reproduce the structures of several elements in white dwarfs, such as the isotopes of $C$ and $^{16} O$ , except for the unnaturally deeply bound state $^{4}$ He. Furthermore, we predict the characteristics of white dwarfs composed of atom-like units and the gravitational waves stemming from binary white dwarf inspirals incorporating tidal deformability contributions up to the 2.5 post-Newtonian order. These results shed light on the structure of white dwarfs and provide valuable information for future gravitational wave detection. This methodological advancement allows for a cohesive analysis of white dwarfs, neutron stars, and the nuclear pasta within a unified theoretical framework.
Comments:
Published version
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2410.06088 [pdf]
Commun.Theor.Phys.(2025)·3 citations
04
[Submitted on 8 Oct 2024]
Motivations for Early High-Profile FRIB Experiments
B. Alex Brown🇮🇳 · Alexandra Gade🇮🇳 · S. Ragnar Stroberg🇺🇸 · Jutta Escher🇺🇸 · Kevin Fossez🇺🇸 · Pablo Giuliani🇺🇸 · Calem R. Hoffman🇺🇸 · Witold Nazarewicz🇮🇳 · Chien-Yeah Seng🇺🇸 · Agnieszka Sorensen🇺🇸 · Nicole Vassh🇨🇦 · Daniel Bazin🇮🇳 and 30 other authors
This white paper is the result of a collaboration by those that attended a workshop at the Facility for Rare Isotope Beams (FRIB), organized by the FRIB Theory Alliance (FRIB-TA), on Theoretical Justifications and Motivations for Early High-Profile FRIB Experiments. It covers a wide range of topics related to the science that will be explored at FRIB. After a brief introduction, the sections address: (II) Overview of theoretical methods, (III) Experimental capabilities, (IV) Structure, (V) Near-threshold Physics, (VI) Reaction mechanisms, (VII) Nuclear equations of state, (VIII) Nuclear astrophysics, (IX) Fundamental symmetries, and (X) Experimental design and uncertainty quantification.
Comments:
227 pages, 24 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2410.06144 [pdf]
J.Phys.G(2025)·29 citations
05
[Submitted on 9 Oct 2024]
Investigation of 90,92Zr(n,{\gamma}) 91,93Zr in the s process nucleosynthesis
Abdul Kabi · Zain Ul Abideen · Jameel-Un Nabi · Dawar Khan
The neutron capture rates and Maxwellian averaged cross sections (MACS) for 90Zr(n,{\gamma}) 91Zr and 92Zr(n,{\gamma}) 93Zr processes have been computed within the framework of Talys v1.96. The effects of phenomenological nuclear level density (NLD) parameters and the gamma strength functions (GSFs) on Maxwellian averaged cross sections and neutron capture rates are examined both quantitatively and qualitatively. The present model based computed data for MACS and reaction rates gives a good comparison with the existing literature. The fine-tuning of the statistical models nuclear properties (level density and gamma-ray strength) to reproduce experimental data will allow the detailed investigation of the s process network.
Comments:
16 pages 2 figures 3 tables
Subjects:
Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR)
arXiv:
2410.06603 [pdf]
Z.Naturforsch.A(2024)·1 citation
06
[Submitted on 9 Oct 2024]
Re-analysis of the Gamow-Teller distributions for N=Z nuclei, 24Mg, 28Si, and 32S
Jameel-Un Nabi · Abdul Kabir · Tuncay Bayram
The Gamow-Teller (GT) strength distributions of sd shell N=Z nuclei ( $^{24}$ Mg, $^{28}$ Si, and $^{32}$ S) are investigated within the framework of proton-neutron quasi particle random phase approximation (pn QRPA) using a deformed basis. The nuclear properties of these special nuclei were investigated by the Relativistic Mean Field (RMF) model. The RMF framework with density-dependent interactions (DD-PC1 and DD-ME2) was employed to compute ground-state deformation parameters (beta 2) using potential energy curves. The $β_{2}$ values computed from the RMF and the finite range droplet model (FRDM) were employed as a free parameter in the pn QRPA calculation to investigate the resulting GT strength distributions.The present model-based analyses compare well with the observed data.
Comments:
14 pages 1 table 4 figures
Subjects:
Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR)
arXiv:
2410.06619 [pdf]
Chin.J.Phys.(2024)·3 citations
07
[Submitted on 9 Oct 2024]
Subtleties in the calculation of correlation functions for hot and dense systems
Sebastian Töpfel🇩🇪 · Andreas Geißel🇩🇪 · Jens Braun🇩🇪
We discuss subtleties in the calculation of loop integrals in studies of hot and dense systems as they appear in both perturbative and non-perturbative approaches. To be specific, we address subtleties which appear in situations where the order of integration, differentiation, and limit processes plays a crucial role. For example, this applies to computations of the effective action and the computation of momentum-dependent correlation functions. In particular, the zero-temperature limit is delicate in systems with fermions because of the presence of discontinuities at the Fermi surface. We provide a general discussion of scenarios where the computation and evaluation of loop integrals in the context of relativistic theories requires particular attention as a change of the order of the involved mathematical operations may lead to a different result. Our general considerations are then illustrated with the aid of concrete examples, namely by the computation of masses from fully momentum-dependent correlation functions in the context of the Gross-Neveu-Yukawa model and quantum electrodynamics.
Comments:
22 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Theory (hep-th)
arXiv:
2410.06674 [pdf]
PRD(2025)·4 citations
08
[Submitted on 9 Oct 2024]
Study of $β^{+}$ /EC-decay properties of $s d$ shell nuclei using nuclear shell model
Surender · Vikas Kumar · Praveen C. Srivastava
Our study employs the nuclear shell model to systematically compute the half-lives of $β$ -decay for nuclei in the mass range of $A = 18 - 39$ , encompassing the majority of $s d$ shell nuclei. This analysis utilizes the USDB and SDNN Hamiltonians. The theoretical outcomes contain calculations of various parameters such as $Q$ -values, half-lives, excitation energy, log $f t$ values, and branching ratios. We explore these results with axial-vector coupling constant for weak interactions, denoted as $g_{A}$ $(= 1.27)$ , and $κ$ value $(= 6289)$ . We perform calculations of Gamow Teller matrix elements for 116 decay processes to calculate the quenching factor; we found a quenching factor of $q = 0.794 \pm 0.05$ for the USDB interaction and $q = 0.815 \pm 0.04$ for the SDNN interaction. We have also calculated superallowed transitions $0^{+} \to 0^{+}$ for seven nuclei. Further, we have also included the electron capture phase space factor for the required nuclei to calculate the half-lives. This inclusion leads to small contribution in results, particularly for nuclei where electron capture (EC) plays a significant role. The overall results are in agreement with the experimental data.
Comments:
16 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2410.06747 [pdf]
Annals Phys.(2024)·4 citations

Affiliations

first authorsco-authorsvia INSPIRE