Nuclear Theory·nucl-th

Friday·July 25, 2025

15 papers—5 primary·10 cross-listed

01
[Submitted on 24 Jul 2025]
Impact of spin polarization on transport and thermodynamic coefficients
De-Xian Wei🇨🇳
This work investigates the influence of parton spin polarization on effective transport and thermodynamic coefficients in noncentral light- and heavy-ion collisions. To model this influence, I consider two sources of spin polarization: thermal vorticity, induced by angular momentum, and thermal shear, arising from local velocity gradients. Using a novel kinetic theory framework, one finds that transport and thermodynamic coefficients -- including the speed of sound squared $c_{s}^{2}$ , specific shear viscosity $η / s$ , specific bulk viscosity $ζ / s$ , and mean free path $λ$ -- are substantially modified by spin polarization effects. Among the two sources, thermal vorticity-induced spin polarization dominates the modifications to these coefficients. Moreover, both $c_{s}^{2}$ and $ζ / s$ exhibit a nonmonotonic dependence on the collision energy, and the associated scaling behaviors potentially serve as indicators of the critical phenomena of quantum chromodynamics.
Comments:
10 pages, 6 figures, publish version
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2507.18038 [pdf]
PRC(2025)·1 citation
02
[Submitted on 24 Jul 2025]
Re-examination of fusion hindrance in astrophysical $^{12}$ C+ $^{12}$ C and $^{12}$ C+ $^{13}$ C reactions
Kotaro Uzawa · Kouichi Hagino
To determine the energy dependence of fusion cross sections at extremely low energies is crucial for various astrophysical processes. In the previous study by Jiang et al. [Phys. Rev. C75, 015803 (2007)], it was concluded that fusion cross sections for the $^{12}$ C+ $^{12}$ C system rapidly drop off as the energy decreases. We here re-examine this hindrance phenomenon. While the previous study fitted the logarithmic slope $L (E)$ of fusion cross sections with a function of $L (E) = A + B / E^{n}$ and searched the optimum value of $A$ and $B$ with $n = 1.5$ , we refit the data with the same function for $L (E)$ but by releasing the restriction on $n$ . We find that the optimum values of $n$ significantly deviates from $n = 1.5$ , resulting in the absence of hindrance of fusion cross sections both in the $^{12}$ C+ $^{12}$ C and the $^{12}$ C+ $^{13}$ C systems.
Comments:
6 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Experiment (nucl-ex)
arXiv:
2507.18065 [pdf]
PRC(2025)·3 citations
03
[Submitted on 24 Jul 2025]
Proton-neutron pairing correlations in N=Z nuclei with Deformed Skyrme+pnBCS model
Xin Lian · C.L. Bai · H. Sagawa · H. Q. Zhang
We investigate the effects of neutron-neutron (nn), proton-proton (pp) and proton-neutron (pn) pairing correlations on the ground-states of $N = Z$ even-even $p f$ -shell nuclei by using an axially symmetric deformed Hartree-Fock (HF)+pnBardeen-Cooper-Schrieffer (BCS) model. We adopt a Skyrme energy density functional (EDF) SGII, together with contact volume- and surface-type pairing interactions, whose strengths are adjusted to reproduce empirical pairing gaps of each nucleus. It is shown that the strength of the IS pairing is correlated to the nuclear deformation: for oblate deformation with $- 0.3 < β_{2} < 0.0$ , a stronger IS pairing is required to reproduce the empirical pairing gap, while for prolate deformation a weaker one is enough. Among the eight $N = Z$ nuclei, we found that $^{64}$ Ge, $^{68}$ Se and $^{72}$ Kr show the dominance of isovector (IV) spin-singlet superfluidity, while lighter 5 nuclei $^{44}$ Ti, $^{48}$ Cr, $^{52}$ Fe, $^{56}$ Ni and $^{60}$ Zn exhibit the coexistence of IV spin-singlet and isoscalar (IS) spin-triplet superfluidities. We found also that the IS abnormal density always exhibits the oblate deformation, regardless of whether the normal density is prolate, spherical or oblate.
Comments:
9 pages, 8 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2507.18124 [pdf]
2 citations
04
[Submitted on 24 Jul 2025]
Investigating $^{238}$ U Deformation via Dilepton Production in Relativistic Heavy-Ion Collisions
Wen-Hao Zhou🇨🇳 · Lu-Meng Liu🇨🇳 · Che Ming Ko🇺🇸 · Kai-Jia Sun🇨🇳 · Jun Xu🇨🇳
Due to their weak coupling to the strongly interacting matter produced in relativistic heavy-ion collisions, dileptons serve as a sensitive probe of the initial geometry of the colliding nuclei. In this study, we investigate the influence of initial nuclear quadrupole deformation, characterized by the parameter $β_{2}$ , on dilepton production in $U + U$ collisions at $s_{N N} = 196$ GeV. The analysis is varried out using a modified multiphase transport model in which partonic interactions are described by the Nambu-Jona-Lasinio model. We observe a clear linear dependence of dilepton yields on $β_{2}^{2}$ in both the low-mass region (LMR, $< 1 G e V / c^{2}$ ) and intermediate-mass region (IMR, $1 - 3 G e V / c^{2}$ ) of the dilepton spectrum for the most central collisions. Also, dilepton production in the IMR region exhibits a stronger sensitivity to nuclear deformation than in the LMR, reflecting the dominance of earlier partonic processes in this mass range. These results suggest that precise measurements of dilepton yields in relativistic heavy-ion collisions can provide a viable means to determine the deformation parameter $β_{2}$ of $^{238}$ U.
Comments:
6 pages with 5 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2507.18189 [pdf]
PLB(2026)·0 citations
05
[Submitted on 24 Jul 2025]
Neutron Star Core-Crust Transition and Crustal Moment of Inertia: Systematic Implications of Higher-Order Symmetry Energy in the Nuclear Equation of State
W. M. Seif · A. S. Hashem
We investigate how higher-order symmetry-energy coefficients of the equation of state (EOS) describing $n p e μ$ core matter impact key neutron star (NS) properties at its crust inner edge, its moment of inertia and corresponding crustal fraction, threshold conditions for direct Urca process, adiabatic index, and related structure observables. Our analysis employs a comprehensive set of CDM3Y-IVF1 equations of state, derived from the M3Y-Paris nucleon-nucleon interaction within a non-relativistic Hartree-Fock framework, covering a wide range of nuclear matter stiffness, from soft ( $K_{0} = 150$ MeV) to extremely stiff (330 MeV) regimes. Our analysis reveals that the stiffer EOS characterized by higher isoscalar incompressibility ( $K_{0}$ ) and fourth-order symmetry-energy skewness ( $Q_{4}$ ) coefficients, coupled with diminished negative values of isoscalar $Q_{0}$ and $H_{0}$ , and isovector $K_{4}$ , $K_{τ 4}$ , $I_{2, 4}$ , and $G_{2}$ coefficients, systematically increase the estimated core-crust transition pressure, density, and charged-particle ( $p, e, μ$ ) fractions, and their threshold values for direct Urca process, as well as the total NS moment of inertia and its crustal fraction, and the central adiabatic index. Simultaneously, they yield less central fraction of $p$ , $e$ , and $μ$ , and reduced fractional crust thickness and moment of inertia for the maximum NS mass supported by a certain EOS. Conversely, enhanced values of the isoscalar kurtosis $I_{0}$ and $G_{0}$ symmetry coefficients, and of the higher-order $Q_{2}$ , $H_{2}$ , $K_{6}$ and $K_{τ 6}$ coefficients, combined with diminished negative contributions from $K_{2}$ and $K_{τ 2}$ , produce systematically opposite effects on the mentioned NS quantities, reversing their trends with $K_{0}$ .
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2507.18384 [pdf]
PRC(2025)·4 citations
06
[Submitted on 23 Jul 2025] (cross-list from hep-ph)
Decoding the proton's gluonic density with lattice QCD-informed machine learning
Brandon Kriesten🇺🇸 · Alex NieMiera🇺🇸 · William Good🇺🇸 · T.J. Hobbs🇺🇸 · Huey-Wen Lin🇺🇸
We present a first machine learning-based decoding of the gluonic structure of the proton from lattice QCD using a variational autoencoder inverse mapper (VAIM). Harnessing the power of generative AI, we predict the parton distribution function (PDF) of the gluon given information on the reduced pseudo-Ioffe-time distributions (RpITDs) as calculated from an ensemble with lattice spacing $a \approx 0.09$ fm and a pion mass of $M_{π} \approx 310$ MeV. The resulting gluon PDF is consistent with phenomenological global fits within uncertainties, particularly in the intermediate-to-high- $x$ region where lattice data are most constraining. A subsequent correlation analysis confirms that the VAIM learns a meaningful latent representation, highlighting the potential of generative AI to bridge lattice QCD and phenomenological extractions within a unified analysis framework.
Comments:
7 pages, 3 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2507.17810 [pdf]
PLB(2026)·4 citations
07
[Submitted on 23 Jul 2025] (cross-list from astro-ph.HE)
Collapsar Disk Outflows III: Detectable Neutrino and Gravitational Wave Signatures
Rodrigo Fernández🇨🇦 · Silas Janke🇨🇦 · Coleman Dean🇨🇦 · Irene Tamborra🇩🇰
We investigate the neutrino and gravitational wave (GW) signals from accretion disks formed during the failed collapse of a rotating massive star (a collapsar). Following black hole formation, a neutrino-cooled, shocked accretion disk forms, which displays non-spherical oscillations for a period of seconds before becoming advective and exploding the star. We compute the neutrino and GW signals (matter quadrupole, frequencies $≲ 100$ Hz) from collapsar disks using global axisymmetric, viscous hydrodynamic simulations. The neutrino signal with typical energies of O $(10)$ MeV is maximal during the neutrino-cooled (NDAF) phase that follows shock formation. This phase lasts for a few seconds and is easily detectable within O $(10 - 100)$ kpc by the IceCube Neutrino Telescope. Additional neutrino signatures from a precursor equatorial shock and by stochastic accretion plumes during the advective phase are detectable within the galaxy. The GW signal during the NDAF phase is detectable in the galaxy by current and next-generation ground-based observatories. The explosion (memory) GW signal is similar to that of standard core-collapse supernovae and can be probed with a deci-Hertz space-based detector. Shock oscillations during the NDAF phase impart time variations with frequency O $(10 - 100)$ Hz to the neutrino and GW signals, encoding information about the shock dynamics and inner disk. These time variations can be detectable in neutrinos by IceCube within O $(1 - 10)$ kpc depending on progenitor model, flavor transformation scenario, and detailed properties of the angular momentum transport mechanism.
Comments:
Accepted by PRD with minor changes. Raw time series data available at https://doi.org/10.5281/zenodo.17299306
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2507.17836 [pdf]
PRD(2025)·1 citation
08
[Submitted on 23 Jul 2025] (cross-list from hep-ph)
Constraints on millicharged particles from nuclear gamma-decays
Ting Gao🇺🇸 · Maxim Pospelov🇺🇸
We consider nuclear gamma decays and $γ$ -emitting reactions that can be an efficient source of hypothetical millicharged particles ( $χ$ ). In particular, we revisit the production of millicharged particles in nuclear reactor environment, pointing out that $γ$ cascades from $^{239}$ U is an overlooked yet a powerful source of $χ χ ˉ$ pairs. This leads to an increased flux compared to previous studies. We then apply new estimates of the flux to derive novel limits on the value of millicharge, $ε = Q_{χ} / e$ , from the electron recoil searched for in a variety of experiments placed in proximity to the reactor cores. The derived limits on $ε$ are the strongest in the interval of masses $\sim 0.7 - 2$ MeV. We also derive the MCP flux from the Sun and point out potential sensitivity of the low-threshold dark matter search experiments.
Comments:
19 pages, published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2507.17955 [pdf]
PRD(2026)·7 citations
09
[Submitted on 24 Jul 2025] (cross-list from astro-ph.HE)
Hyperonic degrees of freedom in binary neutron star mergers
Laura Tolos · Hristijan Kochankovski · Angels Ramos · Georgios Lioutas · Sebastian Blacker · Andreas Bauswein
We analyze the influence of hyperons in binary neutron star mergers considering several different equations of state that include hyperons. By running a large set of simulations, we study the impact of the thermally produced hyperons on the gravitational-wave spectral features, the temperature evolution of the remnant, the mass ejecta and the threshold mass for prompt collapse to a black hole. Models with hyperons tend to stand out in the relation between the dominant postmerger gravitational-wave frequency and the tidal deformability of massive stars. Moreover, the averaged temperature of the remnant is reduced for hyperonic models. The mass ejection of the mergers is tentatively enhanced when hyperons are present in comparison to nucleonic EoSs leading to similar stellar properties of cold neutron stars, whereas the threshold mass for prompt black-hole formation is reduced by about 0.05~ $M_{⊙}$ compared to the nucleonic models.
Comments:
8 pages, 4 figures, contribution based on the keynote parallel talk at the 21st International Conference on Hadron Spectroscopy and Structure (HADRON2025), 27 - 31 March, 2025, Osaka University, Japan
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2507.18213 [pdf]
PoS(2026)·0 citations
10
[Submitted on 24 Jul 2025] (cross-list from hep-ph)
New superconvergence relations for spin and tensor structure functions of $γ γ$ fusion
Vladimir Pascalutsa (JGU Mainz)🇩🇪
The Burkhardt--Cottingham sum rule is an exact superconvergence relation for a spin-structure function, derived from general principles of light absorption and scattering, and valid at any momentum transfer $Q^{2}$ . I illustrate how a class of such relations emerges from the Siegert point, an unphysical kinematical point where both the probe and the target are at rest. From light-by-light scattering, new sum rules for $γ^{*} γ^{*}$ fusion are emerging, valid for arbitrary photon virtualities. Regarding the convergence of these relations, there is a simple argument for the suppression of longitudinal photon polarizations at high energy. Among its consequences is the prediction of $σ_{L} / σ_{T} \to 0$ at high energy, for the ratio of unpolarized nucleon photoabsorption cross sections.
Comments:
7 pages, no figures; miscellaneous revisions suggested by referees, title changed, another new relation added
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2507.18234 [pdf]
PLB(2025)·0 citations
11
[Submitted on 24 Jul 2025] (cross-list from hep-ph)
Study of $Λ p$ and $Λ ˉ p$ scatterings via quasipotential Bethe-Salpeter equation
Yaning Chen🇨🇳 · Jun He🇨🇳
Motivated by recent BESIII measurements of the $Λ p \to Λ p$ and $Λ ˉ p \to Λ ˉ p$ scattering processes, we investigate these reactions within the framework of the quasipotential Bethe-Salpeter equation using an effective Lagrangian approach. The interaction potentials are constructed via a one-boson-exchange model incorporating pseudoscalar, scalar, and vector meson exchanges, along with coupled-channel effects from the $Σ N$ and $Σ ˉ N$ channels. For the $Λ p \to Λ p$ reaction, the total cross sections from threshold up to $s = 2.5 GeV$ are well reproduced. A mild enhancement near the $Σ N$ threshold is attributed to coupled-channel dynamics. Using parameters constrained by the total cross section data, our model also predicts differential cross sections at $s = 2.24 GeV$ , which exhibit weak angular dependence, consistent with experimental observations. Partial-wave analysis indicates that the $1^{+}$ partial wave dominates over the entire energy range, while the $0^{+}$ wave plays a significant role near threshold. For the $Λ ˉ p \to Λ ˉ p$ reaction, our predicted total cross sections show good agreement with the BESIII data. The $1^{-}$ partial wave is found to dominate in most of the energy region. Notably, the calculated differential cross sections exhibit a strong forward peaking behavior, consistent with experimental findings and understood as resulting from constructive interference among various partial waves. This forward-peaked angular distribution persists across a range of energies, highlighting the distinct dynamics of the $Λ ˉ p$ interaction.
Comments:
8 pages, 6 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2507.18415 [pdf]
PLB(2025)·3 citations
12
[Submitted on 24 Jul 2025] (cross-list from quant-ph)
Three-qubit encoding in ytterbium-171 atoms for simulating 1+1D QCD
William Huie🇺🇸 · Cianan Conefrey-Shinozaki🇺🇸 · Zhubing Jia🇺🇸 · Patrick Draper🇺🇸 · Jacob P. Covey🇺🇸
Simulating nuclear matter described by quantum chromodynamics using quantum computers is notoriously inefficient because of the assortment of quark degrees of freedom such as matter/antimatter, flavor, color, and spin. Here, we propose to address this resource efficiency challenge by encoding three qubits within individual ytterbium-171 atoms of a neutral atom quantum processor. The three qubits are encoded in three distinct sectors: an electronic "clock" transition, the spin-1/2 nucleus, and the lowest two motional states in one radial direction of the harmonic trapping potential. We develop a family of composite sideband pulses and demonstrate a universal gate set and readout protocol for this three-qubit system. We then apply it to single-flavor quantum chromodynamics in 1+1D axial gauge for which the three qubits directly represent the occupancy of quarks in the three colors. We show that two atoms are sufficient to simulate both vacuum persistence oscillations and string breaking. We consider resource requirements and connections to error detection/correction. Our work is a step towards resource-efficient digital simulation of nuclear matter and opens new opportunities for versatile qubit encoding in neutral atom quantum processors.
Comments:
W.H. and C.C.S. contributed equally to this work
Subjects:
Quantum Physics (quant-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th); Atomic Physics (physics.atom-ph)
arXiv:
2507.18426 [pdf]
PRX Quantum(2026)·7 citations
13
[Submitted on 24 Jul 2025] (cross-list from hep-ph)
Three-flavor neutrino oscillations using the Phase Space Approach
Mariane Mangin-Brinet🇫🇷 · Angel Bauge🇫🇷 · Denis Lacroix🇫🇷
The Phase-Space Approximation (PSA) approach, originally applied in [Phys. Rev. D 106, 123006 (2022)] to describe neutrino oscillations from a stellar object in the two-flavor limit, is extended here to describe the more realistic case where neutrinos can oscillate between three different flavors. The approach is successfully validated against the exact solutions up to eight neutrinos. In all cases where the exact solution is feasible, the PSA provides excellent reproduction of the neutrino oscillation dynamics. By replacing the full problem with a set of simple mean-field equations, the PSA offers a versatile, predictive, and easily parallelizable approach for tackling three-flavor problems. This enables the simulation of large-scale neutrino oscillations, as illustrated here with simulations involving up to 300 neutrinos. Additionally, the method provides insight into the system's equilibration properties.
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2507.18482 [pdf]
PRD(2026)·7 citations
14
[Submitted on 24 Jul 2025] (cross-list from nucl-ex)
Probing Spin and Lifetime Correlations in Entangled Hyperon-AntiHyperon Pairs
Aihong Tang🇺🇸
Quantum entanglement has now been demonstrated in several hadronic systems, revealing that non-classical spin correlations survive even through the strong-interaction hadronization process. To date, however, all studies have focused exclusively on angular observables, leaving the possibility untouched that quantum coherence might also influence the decay times of entangled partners. In this work we propose data-driven tests of spin-lifetime and lifetime-lifetime correlations for Lambda-antiLambda pairs produced in high-energy collisions. By examining the opening-angle distribution in slices of Delta t, constructing a pair-wise spin-lifetime correlator, and testing a simple lifetime-lifetime covariance, we search for deviations from independent exponential decay that align with known spin correlations. Observation of nonzero lifetime correlations would compel a reassessment of how entanglement manifests in decaying systems, revealing hitherto unexplored temporal coherence.
Comments:
6 pages
Subjects:
Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2507.18507 [pdf]
PLB(2025)·6 citations
15
[Submitted on 24 Jul 2025] (cross-list from hep-ph)
Rapidity-Dependent Spin Decomposition of the Nucleon
Florian Hechenberger🇺🇸 · Kiminad A. Mamo🇺🇸 · Ismail Zahed🇺🇸
We show that the two-dimensional Fourier transform of the generalized parton distributions (GPDs) has two distinct interpretations: at zero skewness ( $η = 0$ ) it yields the familiar impact-parameter density, while at finite skewness ( $η \neq = 0$ ) it encodes a genuine parton-nucleon correlation whose norm decreases predictably with the rapidity gap $Δ y = 2 artanh η$ . This rapidity dependence produces universal rapidity-modified Ji identities linking helicity, orbital, and total angular momenta analytically. Using linear open- and closed string Regge trajectories constrained by empirical PDFs, spectroscopy and form factor data, we obtain the leading twist GPDs $H, E, H$ across the full $(x, η, t)$ range. Numerical Mellin Barnes inversion agrees with existing lattice data and yields rapidity resolved predictions for Jefferson Lab 12 GeV, the Electron Ion Collider, and forthcoming lattice studies.
Comments:
v1: 7 pages, 5 figures; v2: restructured manuscript, published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2507.18615 [pdf]
PRD(2026)·7 citations

Affiliations

first authorsco-authorsvia INSPIRE