Nuclear Theory·nucl-th

Tuesday·December 2, 2025

18 papers—11 primary·7 cross-listed

12
Gravitational form factors of the baryon octet in holographic QCD
Zhibo Liu🇯🇵 · Hiroaki Nakajima🇨🇳 · Hiroaki Abuki🇯🇵 · Akira Watanabe🇯🇵
The gravitational form factors (GFFs) of the baryon octet, including hyperons, are investigated in a bottom-up holographic QCD model that explicitly incorporates the SU(3) flavor symmetry breaking through the strange quark mass. We fit the model parameters to reproduce the empirical masses of the baryon octet and examine the dependence of GFFs on the probe momentum. Our numerical results show distinct differences in the GFFs across the baryon octet. The computed GFFs are found to be in reasonable agreement with available lattice QCD results for the non-strange/nucleon sector. We also calculate the gravitational radii of the baryon octet and find that they decrease with increasing strangeness, indicating that heavier hyperons are more compact.
↳ hep-phnucl-thJHEP(2026)·2 citations
13
A Review on Intense Electromagnetic Fields in Heavy-Ion Collisions: Theoretical Predictions and Experimental Results
Diyu Shen🇨🇳 · Jinhui Chen🇨🇳 · Xu-Guang Huang🇨🇳 · Yu-Gang Ma🇨🇳 · Aihong Tang🇺🇸 · Gang Wang🇺🇸
In heavy-ion collisions at relativistic energies, the incident nuclei travel at nearly the speed of light. These collisions deposit kinetic energy into the overlap region and create a high-temperature environment where hadrons ``melt'' into deconfined quarks and gluons. The spectator nucleons, which do not undergo scatterings, generate an ultra-intense electromagnetic field -- on the order of $1 0^{18}$ Gauss at Relativistic Heavy-Ion Collider, and $1 0^{19}$ Gauss at the Large Hadron Collider. These powerful electromagnetic fields have a significant impact on the produced particles, not only complicating the study of particle interactions but also inducing novel physical phenomena. To explore the nature of these fields and their interactions with deconfined quarks, we provide a detailed overview, encompassing theoretical estimations of their generation and evolution, as well as experimental efforts to detect them. We also provide physical interpretations of the discovered results and discuss potential directions for future investigations.
↳ nucl-exhep-phnucl-thResearch(2025)·24 citations
14
Thermal conduction and thermopower of inner crusts of magnetized neutron stars
Henrik Danielyan · Arus Harutyunyan · Armen Sedrakian
We compute the thermal conductivity and thermoelectric power (thermopower) of the inner crust of compact stars across a broad temperature-density domain relevant for proto-neutron stars, binary neutron-star mergers, and accreting neutron stars. The analysis covers the transition from a semi-degenerate to a highly degenerate electron gas and assumes temperatures above the melting threshold of the nuclear lattice, such that nuclei form a liquid. The transport coefficients are obtained by solving the Boltzmann kinetic equation in the relaxation-time approximation, fully incorporating the anisotropies generated by non-quantizing magnetic fields. Electron scattering rates include (i) dynamical screening of the electron-ion interaction in the hard-thermal-loop approximation of QED, (ii) ion-ion correlations within a one-component plasma, and (iii) finite nuclear-size effects. As an additional refinement, we evaluate electron-neutron scattering induced by the coupling of electrons to the anomalous magnetic moment of free neutrons; this contribution is found to be subdominant throughout the parameter range explored. To assess the sensitivity of transport coefficients to the underlying microphysics, we perform calculations for several inner-crust compositions obtained from different nuclear interactions and many-body methods. Across most of the crust, variations in relaxation times and in the components of the anisotropic thermal-conductivity and thermopower tensors reach up to factors 3-4 and 1.5-2, respectively, with the exception of the region where pasta phases are expected. These results provide updated, composition-dependent microphysical inputs for dissipative magneto-hydrodynamic simulations of warm neutron stars and post-merger remnants, where anisotropic heat and charge transport are of critical importance.
↳ astro-ph.HEastro-ph.SRnucl-th0 citations
15
Exotic $T_{c s ˉ 0}^{a} (2900)^{0}$ and $T_{c s ˉ 0}^{a} (2900)^{++}$ states in Born-Oppenheimer approximation
Halil Mutuk🇹🇷
We employ Born-Oppenheimer approximation to the $T_{c s ˉ 0}^{a} (2900)^{0}$ and $T_{c s ˉ 0}^{a} (2900)^{++}$ states observed by the LHCb Collaboration and study mass spectrum and root-mean-square radius values. For this purpose, we use dynamical diquark model. We assume that strange quark is a heavy for the usage of Born-Oppenheimer approximation. Our results strongly indicate that the $T_{c s 0}^{a} (2900)$ states are best described as composed of axial-vector (spin-1) diquark pairs. Furthermore, the calculated root-mean-square radius, $⟨ r^{2} ⟩^{1/2} \approx 0.70 - 0.80$ fm, which is significantly less than 1 fm, provides compelling evidence that these are compact tetraquarks rather than loosely bound hadronic molecules.
↳ hep-phhep-exhep-latnucl-thPRD(2026)·4 citations
16
Linear realization of SU(3) parity doublet model for octet baryons with bad diquark
Bikai Gao🇯🇵 · Atsushi Hosaka🇯🇵
We construct a linear $S U (3)_{L} \times S U (3)_{R}$ parity doublet model for octet baryons. Our model employs the $(3, 3 ˉ) + (3 ˉ, 3)$ and $(3, 6) + (6, 3)$ chiral representations while excluding the $(8, 1) + (1, 8)$ representation. Through systematic analysis, we demonstrate that the $(3, 6) + (6, 3)$ representation containing symmetric ``bad'' diquarks, despite being energetically disfavored, is essential for reproducing the correct baryon mass hierarchy, particularly the $Σ$ $Ξ$ mass ordering. The model incorporates both spontaneous and explicit chiral symmetry breaking, with the latter implemented through bare quark mass terms that properly account for $S U (3)$ flavor breaking effects. Our numerical analysis successfully reproduces the ground-state octet baryon masses and predicts the spectrum of excited states up to 2.5 GeV. For the experimentally challenging $Ξ$ sector, we provide specific predictions for spin-parity assignments: identifying $Ξ (1950)$ as the first positive-parity excitation. The analysis reveals that ground states are dominated by the $(3, 3 ˉ) + (3 ˉ, 3)$ representation, consistent with the preference for ``good'' diquark configurations, while the $(3, 6) + (6, 3)$ contribution remains crucial for the mass spectrum.
↳ hep-phhep-thnucl-thPRD(2026)·4 citations
17
Bayesian inferences on covariant density functionals from multimessenger astrophysical data: Influences of parametrizations of density dependent couplings
Guo-Jun Wei🇨🇳 · Jia-Jie Li🇨🇳 · Armen Sedrakian🇩🇪 · Yong-Jia Wang🇨🇳 · Qing-Feng Li🇨🇳 · Fu-Hu Liu🇨🇳
Covariant density functionals have been successfully applied to the description of finite nuclei and dense nuclear matter. These functionals are often constructed by introducing density dependence into the nucleon-meson couplings, typically through functions that depend only on the vector, i.e., proper baryon density. In this work, we employ a Bayesian framework to investigate how different parametrizations, characterized by distinct functional forms and by their dependencies on vector and scalar densities, affect the properties of dense matter and compact stars. Our analysis demonstrates that although all considered parametrizations yield broadly comparable inferences, the differences in the equation of state and the symmetry energy remain significant at suprasaturation densities, reflecting the sensitivity to the chosen functional form of the density dependence. We find that allowing the nuclear saturation properties in the isoscalar channel, including the skewness coefficient $Q_{s a t}$ , to be freely adjusted provides adequate flexibility for the current modeling of nuclear and neutron star matter. In contrast, the isovector channel requires further refinement, with freedom extended at least up to the curvature coefficient $K_{sy m}$ to capture variations in the symmetry energy and particle composition at high densities. This work advances prior studies by implementing a rational-function parametrization of the density dependence, informed and constrained by multimessenger astrophysical observations.
↳ astro-ph.HEnucl-thPRC(2026)·2 citations
18
Decoding the structure near the $π^{+} π^{-}$ mass threshold in $ψ (3686) \to J / ψ π^{+} π^{-}$ decays
Yun-Hua Chen🇨🇳 · Xiang-Kun Dong🇩🇪 · Feng-Kun Guo🇨🇳 · Christoph Hanhart🇩🇪 · Bastian Kubis🇩🇪
In light of recent high-precision data taken by the BESIII Collaboration, we reconsider the dipion transition $ψ (3686) \to J / ψ π^{+} π^{-}$ . The strong pion-pion final-state interactions are taken into account model-independently by using dispersion theory. We find that we can reproduce the substructure near the $π^{+} π^{-}$ threshold observed experimentally without introducing an extra resonance state. While a helicity-flip amplitude plays an important role for the formation of the dip in the invariant-mass distribution, the virtual exchange of the charmoniumlike exotic $Z_{c} (3900)$ state improves the fit quality only slightly.
↳ hep-phhep-exnucl-thPRD(2026)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE

Gravitational form factors of the baryon octet in holographic QCD

A Review on Intense Electromagnetic Fields in Heavy-Ion Collisions: Theoretical Predictions and Experimental Results

Thermal conduction and thermopower of inner crusts of magnetized neutron stars

Exotic Tcsˉ0a​(2900)0 and Tcsˉ0a​(2900)++ states in Born-Oppenheimer approximation

Linear realization of SU(3) parity doublet model for octet baryons with bad diquark

Bayesian inferences on covariant density functionals from multimessenger astrophysical data: Influences of parametrizations of density dependent couplings

Decoding the structure near the π+π− mass threshold in ψ(3686)→J/ψπ+π− decays

Affiliations

Exotic $T_{c s ˉ 0}^{a} (2900)^{0}$ and $T_{c s ˉ 0}^{a} (2900)^{++}$ states in Born-Oppenheimer approximation

Decoding the structure near the $π^{+} π^{-}$ mass threshold in $ψ (3686) \to J / ψ π^{+} π^{-}$ decays