Nuclear Theory·nucl-th

Thursday·September 4, 2025

19 papers—9 primary·10 cross-listed

01
[Submitted on 2 Sept 2025]
Towards Precise Simulations and Inference for the Neutron EDM
Skyler Degenkolb🇩🇪 · Luigi Favaro🇧🇪 · Peter Fierlinger🇩🇪 · Jennifer Franz🇩🇪 · Husain Manasawala🇩🇪 · Tilman Plehn🇩🇪
Precision measurements of neutron properties, like its permanent electric dipole moment, rely on understanding complex experimental setups in detail. We show how the properties of stored and transported ultracold neutron ensembles can be simulated reliably. In a second step, we illustrate how they can be used for simulation-based inference of the parameters associated with underlying physics processes such as neutron capture or beta decay. Our proof of principle for simulation-based inference confronts a longstanding challenge with ultracold neutrons: low measurement statistics coupled with a complex apparatus.
Comments:
25 pages, 10 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2509.02791 [pdf]
0 citations
02
[Submitted on 3 Sept 2025]
Observation of renormalization group invariance in symmetry-restored nuclear lattice effective field theory
Jia-Ai Shi🇨🇳 · Chen-Can Wang🇨🇳 · Bing-Nan Lu🇨🇳
Renormalization group (RG) invariance implies that the predictions of effective field theory are independent of the momentum cutoffs introduced during regularization. Here we report the first systematic verification of RG invariance for realistic nuclear few-body systems within nuclear lattice effective field theory. To restore broken continuum rotational and Galilean symmetries, we employ Galilean-invariance-restoration counterterms and use a soft momentum regulator. We calibrate the two- and three-body next-to-next-to leading order (N $^{2}$ LO) chiral forces using $A \leq 3$ observables and perform precision quantum Monte Carlo calculations to compute the $^{4}$ He binding energy. The predicted energy remains constant across cutoffs from $250$ ~MeV to $400$ ~MeV and agrees well with the experimental value, with discrepancies of order 100 keV. Our results demonstrate the capability of extracting accurate, cutoff-independent predictions within lattice-regulated \textit{ab initio} nuclear theory.
Comments:
9 pages, 4 figures, version accepted by Phys. Lett. B
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Lattice (hep-lat)
arXiv:
2509.02953 [pdf]
PLB(2026)·3 citations
03
[Submitted on 3 Sept 2025]
A Study on the Triggering of Nucleonic Direct Urca Processes in Neutron Stars of Specific Masses and Their Hyperon Dependence
Yan Xu🇨🇳 · Yufu Shen🇨🇳 · Qi Yuan🇨🇳 · Xiulin Huang🇨🇳 · Yibo Wang🇨🇳
This work aims to analyze how hyperons affect neutrino radiation properties in nucleonic direct URCA processes, expecting to provide useful references for finding evidence of the existence of hyperons in astronomical observations. This analysis is carried out using the GM1 and NL3 parameter sets under the SU(6) and SU(3) flavor symmetries in the relativistic mean field theory framework. Combined with the inferred mass and radius values of PSRs J1231-1411, J0030+0451, and J0740+6620, our results show that nucleonic direct Urca processes are absent in PSR J1231-1411 due to momentum conservation violation. In hyperon-containing PSR J0030+0451 (NL3 parameter set), the nucleonic direct Urca processes involving $e^{-}$ / $μ^{-}$ would occur. A large inferred mass span induces hyperon fraction variations, affecting neutrino emissivity. If the inferred mass of PSR J0030+0451 exceeds approximately 1.8 $M_{⊙}$ , the neutrino luminosity of the nucleonic direct Urca processes under the SU(3) flavor symmetry remains nearly the same as that in npe $μ$ matter, without depending on hyperons. However, it exhibits an obvious hyperon dependence under the SU(6) spin-flavor symmetry. For hyperon-containing J0740+6620, the nucleonic direct Urca processes under the SU(3) flavor symmetry in GM1 parameter set predicts faster neutrino luminosity decline with hyperonic fraction than npe $μ$ matter, and under the SU(6) spin-flavor symmetry in NL3 parameter set it shows monotonic decreasing trend. The research shows that hyperonic fraction significantly affect the neutrino radiation properties of the nucleonic direct URCA processes in neutron stars. Different-mass pulsars (e.g., PSRs J1231-1411, J0030+0451, J0740+6620) exhibit the distinct nucleonic direct URCA processes behaviors, dependent on inferred masses/radii, parameter sets, and theoretical models.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2509.02988 [pdf]
CPC(2026)·1 citation
04
[Submitted on 3 Sept 2025]
Origin of nucleon mass in the light of PSR J0614-3329 with quark-hadron crossover
Bikai Gao🇯🇵 · Yuk-Kei Kong🇯🇵 · Yong-Liang Ma🇨🇳
The recent NICER observation of PSR J0614-3329, revealing the smallest reliably measured neutron star radius of $R = 10.2 9_{- 0.86}^{+ 1.01}$ km at mass $M = 1.4 4_{- 0.07}^{+ 0.06} M_{⊙}$ , provides an unprecedented constraint on the equation of state of dense matter. We investigate the implications of this measurement for the origin of nucleon mass within the parity doublet model framework, which naturally incorporates both chiral variant and chiral invariant mass components. We construct unified equations of state by employing the parity doublet model with isovector scalar meson $a_{0} (980)$ for hadronic matter up to twice nuclear saturation density, smoothly connected to a Nambu-Jona-Lasinio-type quark model at higher densities through a crossover transition. By systematically varying the chiral invariant mass $m_{0}$ and quark matter parameters, we determine which values simultaneously satisfy all current astrophysical constraints, including gravitational wave observations from GW170817, NICER measurements of several pulsars, and the existence of two-solar-mass neutron stars. The inclusion of PSR J0614-3329 dramatically refines the allowed range of the chiral invariant mass from the previous constraint of $580 MeV ≲ m_{0} ≲ 860 MeV$ to $800 MeV ≲ m_{0} ≲ 860 MeV$ , raising the lower bound by approximately 220 MeV. This result indicates that the chiral invariant mass must constitute at least 85\% of the nucleon mass, challenging the traditional picture of nucleon mass generation through spontaneous chiral symmetry breaking alone and highlighting the importance of gluon condensation and other non-chiral mechanisms.
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2509.03008 [pdf]
PRD(2025)·13 citations
05
[Submitted on 3 Sept 2025]
The equation of state for neutron stars with speed of sound constraints via Bayesian inference
Xieyuan Dong🇨🇳 · Hong Shen🇨🇳 · Jinniu Hu🇨🇳 · Ying Zhang🇨🇳
The parametrized equation of state (EOS) of neutron stars is investigated by Bayesian inference method with various constraints from both nuclear physics and modern astronomical observations. The expansion coefficients correspond to the properties of symmetric nuclear matter and the density dependence of the symmetry energy. The empirical values of the symmetry energy at subsaturation density and the density of crust-core phase transition are considered to limit the low-density behavior of EOS, i.e. $L_{sym}$ , while the speed of sound of neutron star matter and mass-radius observations of millisecond pulsars PSR J0030+0451 and PSR J0740+6620 are adopted to eliminate the high-order expansion coefficients, such as $Q_{sat}$ and $Q_{sym}$ . Finally, our analysis reveals that the skewness coefficient $Q_{sat}$ of the energy per nucleon in symmetric nuclear matter (SNM) exhibits the strongest correlation with the speed of sound, constrained to $Q_{sat} = - 69.5 0_{- 31.93}^{+ 16.52} MeV$ , whose uncertainties are much smaller than those of the experiments of heavy-ion collisions. The symmetry energy parameters are determined as follows: slope $L_{sym} = 34.3 2_{- 11.85}^{+ 13.66} MeV$ , curvature $K_{sym} = - 58.4 5_{- 89.46}^{+ 88.47} MeV$ , and skewness $Q_{sym} = 302.2 8_{- 231.89}^{+ 251.62} MeV$ . Additionally, the radii of canonical ( $1.4 M_{⊙}$ ) and massive ( $2.0 M_{⊙}$ ) neutron stars are predicted as $R_{1.4} = 11.8 5_{- 0.15}^{+ 0.06} km$ and $R_{2.0} = 11.4 2_{- 0.35}^{+ 0.23} km$ , respectively, with a maximum mass of $M_{max} = 2.1 2_{- 0.05}^{+ 0.11} M_{⊙}$ . The tidal deformability is $Λ_{1.4} = 303.5 7_{- 45.22}^{+ 47.95}$ at $1.4 M_{⊙}$ , which is consistent with the analysis of the GW170817 event.
Comments:
30 pages, 9 figures, 2 tables, has been accepted by Physical Review D
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2509.03069 [pdf]
PRD(2025)·9 citations
06
[Submitted on 3 Sept 2025]
Suppression of dynamical momentum-space shell by chiral symmetry
Bikai Gao🇯🇵 · Michał Marczenko🇵🇱
We investigate the appearance of quark degrees of freedom in dense isospin-symmetric nuclear matter. We employ the parity doublet model to incorporate chiral dynamics. Specifically, we contrast quarkyonic matter, in which quarks occupy states above the nucleon Fermi surface, with baryquark matter, in which quarks populate states inside the nucleonic Fermi sea. We find that while baryquark matter is generally energetically favored over quarkyonic matter, the self-consistent treatment of the momentum-space shell reveals that purely hadronic matter provides the lowest free energy up to densities well beyond nuclear saturation. Consequently, the contribution of quarks is not relevant within the model's domain of applicability, even though chiral symmetry becomes restored. This demonstrates that the onset of quark degrees of freedom and the restoration of chiral symmetry need not coincide.
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2509.03138 [pdf]
PRC(2026)·2 citations
07
[Submitted on 3 Sept 2025]
Electromagnetic radiation from Quark-Gluon Plasma at finite baryon density
Xiang-Yu Wu🇨🇦 · Charles Gale🇨🇦 · Sangyong Jeon🇨🇦 · Jean-François Paquet🇺🇸 · Björn Schenke🇺🇸 · Chun Shen🇺🇸
Using the Bayesian calibrated iEBE-MUSIC framework, we compute the production of electromagnetic radiation from hot hadronic matter at finite baryon density. Results for thermal photon and thermal dilepton yields are obtained by folding in-medium emission rates with posterior-sampled backgrounds evolved hydrodynamically. We consider different photon sources and analyze the collision-energy dependence of the thermal-to-prompt photon ratio. The sensitivity of the dilepton spectra to the pre-equilibrium stage is explored by considering different initialization procedures. Finally, we examine the impact on dilepton spectra of choosing parameter sets stemming from different Bayesian data analyses.
Comments:
4 pages, 2 figures, proceedings for Quark Matter 2025 conference
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2509.03289 [pdf]
EPJ Web Conf.(2026)·4 citations
08
[Submitted on 3 Sept 2025]
Bayesian analysis of properties of nuclear matter with the FOPI experimental data
Guojun Wei🇨🇳 · Manzi Nan🇨🇳 · Pengcheng Li🇨🇳 · Yongjia Wang🇨🇳 · Qingfeng Li🇨🇳 · Gaochan Yong🇨🇳 · Fuhu Liu🇨🇳
Based on the ultra-relativistic quantum molecular dynamics (UrQMD) transport model, combined with experimental data of directed flow, elliptic flow, and nuclear stopping power measured by FOPI in $^{197} Au +^{197} Au$ collisions at beam energies ( $E_{l ab}$ ) of 0.25 and 0.4 GeV/nucleon, the incompressibility of the nuclear equation of state $K_{0}$ , the nucleon effective mass $m^{*}$ , and the in-medium correction factor ( $F$ , with respect to free-space values) on the nucleon-nucleon elastic cross sections are studied by Bayesian analysis. It is found that both $m^{*}$ and $F$ can be tightly constrained with the uncertainty $\leq$ 15\%, however, $K_{0}$ cannot be constrained tightly. We deduce $m^{*} / m_{0} = 0.7 8_{- 0.10}^{+ 0.09}$ and $F = 0.7 5_{- 0.07}^{+ 0.08}$ with experimental data at $E_{l ab}$ = 0.25 GeV/nucleon, and the obtained values increased to $m^{*} / m_{0} = 0.8 8_{- 0.03}^{+ 0.03}$ and $F = 0.8 8_{- 0.07}^{+ 0.06}$ at $E_{l ab}$ = 0.4 GeV/nucleon. The obtained results are further verified with rapidity-dependent flow data.
Comments:
10 pages, 7 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2509.03406 [pdf]
PRC(2026)·5 citations
09
[Submitted on 3 Sept 2025]
Color-superconducting quarkyonic matter
Christoph Gärtlein🇵🇹 · Oleksii Ivanytskyi🇷🇸 · Violetta Sagun🇬🇧 · Ilídio Lopes🇵🇹
We explore the role of color superconductivity in quarkyonic matter under the conditions of color and electric neutrality at $β$ - and strong equilibrium, as relevant for neutron stars. By explicitly incorporating the color-superconducting pairing gap into the phenomenological model of a smooth transition from hadron to quark matter, we extend the known quarkyonic framework to include this essential aspect relevant at high densities. The momentum dependence of the pairing gap, motivated by the running of the QCD coupling and introduced similarly to chiral quark models with nonlocal interaction, is a novel element of the model that is crucial for enabling the simultaneous onset of all color-flavor quark states in the presence of color superconductivity. While asymptotically conformal behavior of the present model is ensured by construction, we demonstrate that reaching the conformal limit in agreement with the predictions of perturbative QCD is provided by the proper momentum dependence of the thickness of the hadron shell in momentum space. We employ the flexible meta-modeling approach to nuclear matter, analyzing the structure of the hadron shell in momentum space and focusing on the effects of color superconductivity in quarkyonic matter. Similar to the effects induced by the onset of the quarkyonic phase, color superconductivity leads to stiffening of the equation of state of the NS matter. This causes a significant impact on observable properties of neutron stars, which are analyzed and compared to recent astrophysical and theoretical constraints. We argue that the developed model of color-superconducting quarkyonic matter provides a new, consistent tool for studying the scenario of smooth quark-hadron transition in NSs.
Comments:
23 pages, 11 figures, 2 tables
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2509.03517 [pdf]
PRD(2026)·8 citations

Affiliations

first authorsco-authorsvia INSPIRE