Nuclear Theory·nucl-th

Thursday·May 29, 2025

8 papers—4 primary·4 cross-listed

01
[Submitted on 27 May 2025]
Quantum correlation dynamics and in-medium 3 $\leftrightarrow$ 3 collisions of fermions
Wolfgang Cassing
In this study we aim for quantifying the role of in-medium 3 $\leftrightarrow$ 3 collisions for systems of fermions which initially are out-off equilibrium. The formulation of the 3-body dynamics is based on the equations of motion method for identical fermions -- also denoted as quantum correlation dynamics -- and presented in detail. The on-shell 2-body collision integral is briefly reviewed and the on-shell 3-body collision integral is derived on the basis of the same two-body interaction in leading order. The resulting equations obey particle number as well as energy-momentum conservation. For a quantification of the relative impact of 3-body interactions we employ a model study for a homogeneous system in space in a finite box with periodic boundary conditions. We address spin-isospin symmetric nuclear matter systems with momentum distributions that are given by shifted Fermi spheres (without overlap) as encountered in the initial phase of nucleus-nucleus collisions after contact. The results for the relaxation times -- employing an effective 2-body interaction -- are compared to Boltzmann-Uehling-Uhlenbeck (BUU) transport calculations in the continuum limit for the same bombarding energies and are found to agree on the level of a few percent. We find that the additional 3-body interactions reduce the relaxation times up to a factor of 3 at 130 A $\cdot$ MeV. Furthermore, it is shown in BUU transport calculations that an enhanced stopping by 3 $\leftrightarrow$ 3 collisions shows up in the angular distribution of energetic nucleons ( $>$ 60 MeV) e.g. in central $_{45}^{97} R h$ collisions at 40 A $\cdot$ MeV that lead to the formation of a compound nucleus. The angular distribution of the energetic nucleons changes from a slightly forward peaked angular distribution to a slightly sidewards peaked angular distribution which might be controlled experimentally.
Comments:
30 pages, 11 figures, submitted to Phys. Rev. C
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2505.21683 [pdf]
PRC(2025)·1 citation
02
[Submitted on 28 May 2025]
Constraints on the strength of first-order phase transition and its relation to nucleon mass
Bikai Gao🇯🇵
We investigate the constraints on the strength of first-order phase transitions in neutron star matter and its relation to the origin of nucleon mass. By combining the parity doublet model for the hadronic phase, the Nambu-Jona-Lasinio model for quark matter, and the integral constraint framework for intermediate densities, we construct equation of states spanning the full density range relevant to neutron stars. Our approach systematically explores how the chiral invariant mass $m_{0}$ affects the allowable properties of first-order quark-hadron phase transitions. Through comparison with recent neutron star observations, we establish a inverse correlation between the allowed phase transition strength and the chiral invariant mass. Our results demonstrate a direct connection between fundamental questions about the microscopic origin of nucleon mass and macroscopic neutron star observables, providing a novel astrophysical probe of chiral dynamics and QCD physics under extreme conditions.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2505.21970 [pdf]
4 citations
03
[Submitted on 28 May 2025]
Convergence of the $ppp$ correlation function within the hyperspherical adiabatic basis
E. Garrido🇪🇸 · A. Kievsky🇮🇹 · R. Del Grande🇨🇿 · L. Serksnyte🇨🇭 · M. Viviani🇮🇹 · L.E. Marcucci🇮🇹
The computation of the three-particle correlation function involving three hadrons started just recently after the first publications of ALICE measurements. Key elements to be considered are the correct description of the asymptotics, antisymmetrization issues and, in most cases, the treatment of the Coulomb interaction. In the case of the $ppp$ correlation function, a first analysis was done where the hyperspherical adiabatic method was used to determine the $ppp$ wave function at different energies. Although the asymptotic behavior, antisymmetrization issues and the treatment of the Coulomb interaction were discussed in detail, the convergence properties of the adiabatic basis were studied at low energies around the formation of the correlation peak determined mainly by the $J^{π} = 1/ 2^{-}$ and $3/ 2^{-}$ three-body states. Since many and very precise data have been taken or are planned to be measured at energies beyond the peak, we present an analysis of the convergence characteristics of the basis as the energy of the process increases. We show that in order to describe correctly the correlation tail it is necessary to consider three-body states up to $J^{π} = 21/ 2^{-}$ whereas higher states can be considered as free. Once those states are incorporated solving the associate dynamical equations, the agreement with the experimental data is found to be excellent.
Comments:
Submitted for publication, six pages, three figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2505.22190 [pdf]
PLB(2025)·5 citations
04
[Submitted on 28 May 2025]
Neutron Magic Numbers in $s d$ Shell from Nuclear Charge Radii within Neutron-Proton Correction around the Fermi Surface
Yu-Ting Rong🇨🇳 · Ping-Mo Liu🇨🇳 · Dan Yang🇨🇳 · Rong An🇨🇳
Charge radii are sensitive indicators to identify the nuclear structure phenomena throughout the whole nuclide chart. In particular, the shrunken trend of changes of charge radii along a long isotopic chain is intimately associated with the shell quenching effect. In this work, the systematic evolution of charge radii along the proton numbers $Z = 8$ , $10$ , $12$ , $14$ , $18$ isotopes is investigated by a relativistic Hartree Bogoliubov model. A ansatz about neutron-proton correlation around Fermi surface is considered for describing the abnormal behavior of nuclear charge radii. Our results show that the neutron-proton pairing corrections around the Fermi surface lead to a sudden strengthening of the charge radii of these isotopic chains at $N = 8$ , 20 and 28, reflecting the fact that this correction enhances the shell closure across $N = 8$ , 20 and 28. The reproduction of the $N = 14$ charge radius in the Mg isotopes is affected by the way in which pairing correlations are handled, with BCS theory overestimating the shell effect of $N = 14$ , and the Bogoliubov quasiparticle transformation suggests a stronger pairing correlation near the proton Fermi surface, which is more consistent with experimental results. An analysis of the deviations from the theoretical and available experimental data for the charge radii of the 24 selected even-even nuclei shows that the neutron-proton pairing correction around the Fermi surface has an improved effect on the calculation of the charge {radii} using the meson-exchange effective interactions, but it does not help to significantly improve the results calculated by the density-dependent effective interactions.
Comments:
10 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2505.22412 [pdf]
Nucl.Sci.Tech.(2026)·0 citations
05
[Submitted on 27 May 2025] (cross-list from astro-ph.HE)
Prospect of Constraining the EoS of Neutron Stars Using Post-Merger Signals
Soham Mitra🇮🇳 · Praveer Tiwari🇮🇳 · Archana Pai🇮🇳
Post-merger gravitational-wave emission from a binary neutron star merger carries crucial information about the equation of state (EoS) of matter at high temperatures. Current gravitational wave detectors have limited sensitivities at post-merger frequencies in the range [1.5, 4] kHz. Therefore, valuable inferences can only be made after combining information from multiple (BNS) events. Criswell et al. [Phys. Rev. D 107, 043021 (2023)] carries out an injection study to infer the radius posterior for a $1.6 M_{⊙}$ NS by combining the information from injected BNS events via the hierarchical Bayesian inference (HBI) formulation. This formulation utilizes empirical relations that connect the peak frequency of the post-merger remnant with the chirp mass of the system, and the EoS proxy parameter $R_{1.6}$ . In this work, we extend the HBI formulation to other EoS proxy parameters (i.e., the radius of (NS), $R_{1. X}$ , with masses 1.2, 1.4, and 1.8 $M_{⊙}$ ) and combine the four $R_{1. X}$ posteriors through the piecewise polytropic EoS model to obtain measurable constraints on the EoS of the NS. We show that the NS radii can be constrained to within $\sim$ 1 km ( $\sim$ 0.55 km) assuming uniform (astrophysical) prior on $R_{1. X}$ for injections in the A+ noise. We also study systematic biases in the analysis coming from the limitations of empirical relations.
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th); Data Analysis, Statistics and Probability (physics.data-an)
arXiv:
2505.21667 [pdf]
J.Subatomic Part.Cosmol.(2026)·4 citations
06
[Submitted on 28 May 2025] (cross-list from hep-th)
Spin polarization of holographic baryon in strongly coupled fluid
Si-wen Li🇨🇳 · Shu Lin🇨🇳
The spin polarization for baryon in a hydrodynamic medium has been extensively studied in the weakly coupled regime using quantum kinetic theory. As a first study of this problem in the strongly coupled regime, we investigate holographically the spectral function of a probe baryon in the fluid-gravity background. This is done by carefully performing gradient expansion of the Dirac equation in the fluid-gravity background. Different contributions in the expansion are understood in terms of density matrices of the probe baryon and the medium. The resulting spectral functions indicate that the holographic baryonic is polarized as responses to fluid acceleration, shear stress and vorticity. The structures of the responses are similar to those found in weakly coupled studies.
Comments:
28 pages, 4 figures
Subjects:
High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2505.21883 [pdf]
PRD(2025)·4 citations
07
[Submitted on 28 May 2025] (cross-list from hep-ph)
Probing the sensitivity of anisotropic flow coefficients to the initial nuclear structure in pO and OO collisions at the LHC
Aswathy Menon Kavumpadikkal Radhakrishnan🇮🇳 · Suraj Prasad🇮🇳 · Neelkamal Mallick🇫🇮 · Raghunath Sahoo🇮🇳 · Gergely Gábor Barnaföldi🇭🇺
RHIC and LHC have injected $^{16} O$ nuclei in their accelerator complexes with a focus on investigating collectivity and the origin of quark-gluon plasma signatures in small collision systems. The $^{16} O$ nuclei are known to possess clusters of $α$ -particles ( $^{4} He$ ) inside the nucleus. This paper attempts to study the clustered-nuclear-geometry dependence of anisotropic flow coefficients such as elliptic flow ( $v_{2}$ ) and triangular flow ( $v_{3}$ ), which are sensitive to the nuclear geometry of colliding nuclei. The study is performed in pO and OO collisions at $s_{NN} = 9.61$ ~TeV and 7~TeV respectively, employing a hybrid model encompassing IP-Glasma + MUSIC + iSS + UrQMD. The results of the clustered nuclear geometry are compared with those of the Woods\,--\,Saxon nuclear profile. Both initial and final state anisotropies are estimated. This study is thus one of its first kind, where the study of anisotropic flow coefficients for pO and OO collisions is presented using a hybrid hydrodynamics model. While the effect of $α$ -clustering in pO is found to be small, it is significant for each observable studied in OO collisions. It is also observed that the magnitude of this effect has a noteworthy dependence on the size of the \textsuperscript{4}He.
Comments:
14 pages and 8 captioned figures. Same as the published version in Phys. Letts. B
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2505.22367 [pdf]
PLB(2025)·7 citations
08
[Submitted on 28 May 2025] (cross-list from hep-ph)
Renormalizing the Quark-Meson-Diquark Model
Hosein Gholami🇩🇪 · Lennart Kurth🇩🇪 · Ugo Mire🇩🇪 · Michael Buballa🇩🇪 · Bernd-Jochen Schaefer🇩🇪
We present a comprehensive study of the two-flavor Quark--Meson--Diquark (QMD) model by comparing a renormalization approach with a renormalization-group (RG) consistent mean-field formulation based on the functional renormalization group (FRG). The renormalized QMD model allows analytical investigations of key quantities such as the zero-temperature diquark gap and the critical temperature for color superconductivity, ultimately reproducing the exact BCS relation in the high-density limit. We carry out the same analysis for different schemes of RG-consistent QMD models. We show that the RG-consistent approach yields a phase diagram and thermodynamic properties qualitatively similar to those of the renormalized model, provided both are embedded within a unified scheme that ensures consistent vacuum properties. In particular, both treatments recover the Stefan--Boltzmann limit at high densities. On the other hand, whether the BCS relation for the critical temperature is satisfied depends on the details of the RG-consistent setup. Our results highlight the relevance of renormalization and RG-consistent methods for accurately capturing the thermodynamics of QMD and related effective models with diquark degrees of freedom.
Comments:
v2: Major revision: added Fig. 3 and updated Fig. 6 including discussion in the main text. New Appendix D. 31 pages, 6 figures, 2 Tables. Comments are welcomed
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2505.22542 [pdf]
PRD(2026)·22 citations

Affiliations

first authorsco-authorsvia INSPIRE