Nuclear Theory·nucl-th

Thursday·January 1, 2026

21 papers—10 primary·11 cross-listed

01
[Submitted on 30 Dec 2025]
Fluctuations of Temperature in the Polyakov-loop extended Nambu--Jona-Lasinio Model
He Liu🇨🇳 · Peng Wu🇨🇳 · Hong-Ming Liu🇨🇳 · Peng-Cheng Chu🇨🇳
We investigate temperature fluctuations in hot QCD matter using a 3-flavor Polyakov-loop extended Nambu--Jona-Lasinio (PNJL) model. The high-order cumulant ratios $R_{n 2}$ ( $n > 2$ ) exhibit non-monotonic variations across the chiral phase transition, characterized by slight fluctuations in the chiral crossover region and significant oscillations around the critical point. In contrast, distinct peak and dip structures are observed in the cumulant ratios at low baryon chemical potential. These structures gradually weaken and eventually vanish at high chemical potential as they compete with the sharpening of the chiral phase transition, particularly near the critical point and the first-order phase transition. Our results indicate that these non-monotonic peak and dip structures in high-order cumulant ratios are associated with the deconfinement phase transition. This study quantitatively analyzes temperature fluctuation behavior across different phase transition regions, and the findings are expected to be observed and validated in heavy-ion collision experiments through measurements of event-by-event mean transverse momentum fluctuations.
Comments:
9 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2512.23934 [pdf]
Universe(2026)·3 citations
02
[Submitted on 30 Dec 2025]
Towards a bottom-up formulation of spin kinetic theory
Zonglin Mo🇨🇳 · Yi Yin🇨🇳
We develop a bottom-up formulation of spin-kinetic theory for hot and/or dense plasmas. We introduce scalar and axial-vector phase-space functions as dynamical variables that parametrize both spin-averaged and spin-dependent distribution functions. Using spin-dependent Poisson brackets, we derive the corresponding kinetic equations and construct the associated Schwinger-Keldysh action. We further demonstrate how physical observables can be expressed in terms of these dynamical variables through constitutive relations. In the linear response regime, we establish a precise matching between the kinetic-theory and field-theory descriptions of vector and axial Wigner functions under electromagnetic and gravitational perturbations. Our framework provides a complementary approach to describing the dynamics of spin effects in a medium.
Comments:
27 pages, comments are welcome (v2, minor typos correcrted, references updated)
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2512.23960 [pdf]
PRD(2026)·0 citations
03
[Submitted on 30 Dec 2025]
Initial spin fluctuations as a probe of cluster spin structure in $^{16} O$ and $^{20} Ne$ nuclei
Xiang Fan🇨🇳 · Jun-Qi Tao🇨🇳 · Ze-Fang Jiang🇨🇳 · Ben-Wei Zhang🇨🇳
We investigate the imprint of $α$ clustering on initial spin fluctuations in relativistic $^{16} O +^{16} O$ and $^{20} Ne +^{20} Ne$ collisions at $s_{NN} = 5.36$ ~TeV. Utilizing \textit{ab initio} configurations from Nuclear Lattice Effective Field Theory (NLEFT) and phenomenological $α$ -cluster models within a Monte-Carlo Glauber framework, we compute the event-by-event variance of the initial net spin polarization. We find that the strong short-range spin--isospin correlations characteristic of $α$ clusters lead to a significant suppression of spin fluctuations compared to a spherical Woods--Saxon baseline with uncorrelated spins. By constructing a scaled fluctuation observable that accounts for trivial finite-size effects, we demonstrate that this suppression exhibits a non-monotonic centrality dependence sensitive to the detailed cluster geometry. Furthermore, we propose the ratio of scaled spin fluctuations between $^{20} Ne$ and $^{16} O$ systems as a robust probe. Our results predict distinct percent-level deviations from the baseline for clustered nuclei, suggesting that measurements of final-state $Λ$ -hyperon spin correlations can provide novel constraints on the ground-state spin structure of light nuclei.
Comments:
13 pages, 7 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2512.24079 [pdf]
0 citations
04
[Submitted on 30 Dec 2025]
Halo structure of $^{6}$ He from $ab initio$ two-nucleon spatial correlations
Mengyao Huang · Tobias Frederico · Peng Yin · Robert A. M. Basili · Patrick J. Fasano · James P. Vary
We evaluate pairwise correlations using ground state wave functions for $^{4}$ He and $^{6}$ He obtained by $ab initio$ no-core shell model calculations with the Daejeon16 nucleon-nucleon interaction plus Coulomb interaction, to characterize the structures of these two systems. We demonstrate that two-nucleon spatial correlations, specifically the pair-number operator $r^{0}$ and the square-separation operator $r^{2}$ projected on two-body spin $S$ and isospin $z$ components encode important details of the halo structure of $^{6}$ He. We also analyze the single-particle state occupancies and the two-body state occupancies for the ground state of $^{4}$ He and $^{6}$ He. Our results indicate that the two valence neutrons in the ground state of $^{6}$ He dominantly form a spin-singlet configuration. The rms pair separations between core nucleons and halo neutrons of $^{6}$ He are, on average, about 80% larger than pair separations within the swollen and off-centered " $α$ core". We show that this off-centering effect is primarily responsible for the observed increase in point-proton radius $r_{p}$ in $^{6}$ He relative to $^{4}$ He.
Comments:
14 pages, 4 figures, 5 tables
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2512.24123 [pdf]
PRC(2025)·3 citations
05
[Submitted on 30 Dec 2025]
3D solution of the full Faddeev equations for the Nd break-up reaction without 3NF effect
Reza Ramazani-Sharifabadi · Iman Ziaeian
A recently developed three-dimensional formalism for the nucleon-deuteron breakup channel initially considered only the leading-order term of the Faddeev equations, using the nucleon-nucleon T-matrix to compute the breakup amplitude. In the present study, we extend that formalism by solving the full three-nucleon Faddeev equation without three-nucleon-force contributions in a three-dimensional approach in which momentum vectors are used directly as variables. This formalism is well suited for projectile energies in scattering processes above the pion-production threshold, where partial-wave expansions become inefficient. To treat the moving singularities of the free three-nucleon propagator, we introduce a new method that treats these singularities in a manner analogous to the simple poles appearing in the Lippmann-Schwinger equation. This approach evaluates the moving singularities directly through the center-of-mass energy of the 23-subsystem and eliminates the need to partition the q-domain into intervals. The resulting formulation opens a pathway toward a systematic investigation of the complex singularities in few-body scattering processes within the Faddeev framework.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2512.24164 [pdf]
Sci.Rep.(2026)·0 citations
06
[Submitted on 30 Dec 2025]
Nuclear structure properties of $^{184 - 194}$ Pb isotopes and isomers
S. Shukla · P. C. Srivastava
In the present work, we study nuclear structure properties of the $^{184 - 194}$ Pb isotopes within the framework of the nuclear shell-model. We have performed shell-model calculations using KHH7B and KHHE interactions. We have reported results for energy spectra, electromagnetic properties such as quadrupole moment ( $Q$ ), magnetic moment ( $μ$ ), $B (E 2)$ , and $B (M 1)$ transition strengths, and compared the shell-model results with the available experimental data. The shell-model results for the half-lives and seniority quantum numbers ( $v$ ) are also reported for the isomeric states.
Comments:
26 pages, Nuclear Physics A
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2512.24280 [pdf]
NPA(2026)·1 citation
07
[Submitted on 31 Dec 2025]
Dilepton emission as a novel probe of QCD critical point
Gaoqing Cao🇨🇳 · Xiaofeng Luo🇨🇳 · Weijie Fu
In this work, we propose dilepton emission rate (DER) as a sensitive probe of QCD critical point based on the extended Polyakov-quark-meson model. The model could successfully capture two main mechanisms for dilepton production, $π^{\pm}$ and quark-antiquark annihilations on one hand, and self-consistently account for chiral transition and (de-)confinement on the other hand. Along the chemical freezeout lines, all the moments of the DER peak show similar extremal features as those of light quark mass, thus the DER can well reflect the change of chiral symmetry and criticality. More importantly, the DER can be directly measured in heavy ion collisions: Compared to the baryon number fluctuations, the DER fluctuations are found to be more drastic in the critical region and more sensitive to the relative location of the critical point. However, recent statistics of DER in heavy ion collision is not large enough to perform event-by-event measurement, instead we propose to study the baseline subtracted DER: For a given dilepton center of mass, the largest deviation shows up around the point where the light quark mass fluctuation is the strongest.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2512.24646 [pdf]
1 citation
08
[Submitted on 31 Dec 2025]
$S$ -wave $K N$ scattering in a renormalizable chiral effective field theory
Xiu-Lei Ren🇨🇳
We investigate the $s$ -wave $K N$ scattering up to next-to-leading order within a renormalizable framework of covariant chiral effective field theory. Using time-ordered perturbation theory, the scattering amplitude is obtained by treating the leading-order interaction non-perturbatively and including the higher-order corrections perturbatively via the subtractive renormalization. We demonstrate that the non-perturbative treatment is essential, at least at lowest order, in the SU(3) sector of $K N$ scattering. Our NLO study achieves a good description of the empirical $s$ -wave phase shifts in the isospin $I = 1$ channel. An analysis of the effective range expansion yields a negative effective range, consistent with some partial wave analyses but opposite in sign to earlier phenomenological summaries. For the $I = 0$ counterpart, the $K N$ interaction is found to be rather weak and exhibits large uncertainties. Further low-energy $K N$ scattering experiments and lattice QCD simulations are needed to better constrain both $s$ -wave channels.
Comments:
9 pages, 5 figures, 1 table, minor revisions, version to appear in Phys. Rev. D
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2512.24721 [pdf]
PRD(2026)·1 citation
09
[Submitted on 31 Dec 2025]
Non-Equilibrium Dynamics in QCD and Holography
Matthias Kaminski🇺🇸
The plasma generated in heavy ion collisions goes through different phases in its time evolution. While early times right after the collision are governed by far-from equilibrium dynamics, later times are believed to be well described by near-equilibrium dynamics. While the regimes of non-equilibrium are prohibitively complicated to describe within QCD, effective descriptions such as hydrodynamics provide a viable approach. In addition, holographic descriptions allow access to the full non-equilibrium dynamics at strong coupling. In this presentation, we review three examples of such hydrodynamic approaches and corresponding holographic descriptions: 1) non-equilibrium shear viscosity, 2) propagation of non-equilibrium sound waves, and 3) the non-equilibrium chiral magnetic effect.
Comments:
11 pages, 5 figures, contribution to proceeding of XQCD 2025
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex)
arXiv:
2512.24909 [pdf]
J.Subatomic Part.Cosmol.(2026)·3 citations
10
[Submitted on 31 Dec 2025]
Dissipative corrections to the particle momentum spectrum of a decoupling fluid
Francesco Becattini🇮🇹 · Daniele Roselli🇮🇹 · Xin-Li Sheng🇮🇹
We present an \emph{ab initio} calculation within quantum statistical field theory and linear response theory, of the dissipative correction to the momentum spectrum of scalar particles emitted at decoupling (freeze-out) from a relativistic fluid assuming the initial state to be in local thermodynamic equilibrium. We obtain an expansion of the Wigner function of the interacting quantum field in terms of the gradients of the classical thermo-hydrodynamic fields - four-temperature vector and reduced chemical potential - evaluated on the initial local-equilibrium hypersurface, rather than on the decoupling (freeze-out) hypersurface as usual in kinetic theory. The gradient expansion includes an unexpected zeroth order term depending on the differences between thermo-hydrodynamic fields at the decoupling and the initial hypersurface. This term encodes a memory of the initial state which is related to the long-distance persistence of the correlation function between Wigner operator and stress-energy tensor and charged current that is discussed in detail. We address the phenomenological implications of these corrections for the momentum spectra measured in relativistic nuclear collisions.
Comments:
40 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th); Statistical Mechanics (cond-mat.stat-mech); High Energy Physics — Theory (hep-th)
arXiv:
2512.24994 [pdf]
1 citation

Affiliations

first authorsco-authorsvia INSPIRE