Nuclear Theory·nucl-th

Tuesday·March 25, 2025

13 papers—6 primary·7 cross-listed

01
Charge-dependent nucleon-nucleon interaction at N $^{3}$ LO in nuclear lattice effective field theory
Chengxin Wu🇨🇳 · Teng Wang🇨🇳 · Bing-Nan Lu🇨🇳 · Ning Li🇨🇳
The nuclear lattice effective field theory (NLEFT) is an efficient tool for solving nuclear many-body problems, which takes high-fidelity lattice chiral interactions as input and computes nuclear low-energy observables via quantum Monte Carlo techniques. In this work, we present the first next-to-next-to-next-to-leading order (N $^{3}$ LO) chiral forces on the lattice with the isospin-breaking effects fully taken into account. We focus on both the charge-independence breaking (CIB) and charge-symmetry breaking (CSB) effects. Specifically, we include the isospin-breaking effect from the mass difference between the charged and neutral pions in the one-pion-exchange potential (OPEP), the Coulomb force for the $pp$ interaction and the contribution of two additional charge-dependent contact operators. We also explicitly incorporate the two-pion-exchange potentials which was mostly neglected in previous NLEFT calculations. With these improvements, we are able to accurately reproduce the $n p$ and $pp$ scattering phase shifts up to relative momentum $p \sim 200$ MeV as well as the deuteron properties. The construction of these charge-dependent lattice nuclear forces establishes a solid foundation for future high-precision nuclear ab initio calculations within the NLEFT framework.
nucl-thhep-lathep-phnucl-exPRC(2025)·7 citations
02
In-medium nucleon-nucleon cross sections from relativistic ab initio calculations
Tianyu Wang · Hui Tong · Chencan Wang · Xiaoying Qu · Sibo Wang
The in-medium nucleon-nucleon scattering cross section is a pivotal quantity for studying the medium effects of strong interaction, and its precise knowledge is critical for understanding the equation of state for dense matter, intermediate-energy heavy-ion collision dynamics, and related phenomena. In this work, we perform a microscopic investigation of in-medium nucleon-nucleon scattering cross sections, by utilizing the relativistic Brueckner-Hartree-Fock (RBHF) theory with the Bonn potential. The fully incorporation of both positive- and negative-energy states in the RBHF solutions allows us to determine the single-particle potentials, the effective G matrix, and the scattering cross section uniquely. The momentum, density, and isospin dependence of the cross section for pp, nn, and np scattering are studied in detail. Our results provide a solid foundation for future parametrization studies of multiparameter dependency of total scattering cross sections.
nucl-thPRC(2025)·2 citations
03
Effective field theory for weakly bound two-neutron halo nuclei: corrections from neutron-neutron effective range
Davi B. Costa · Masaru Hongo · Dam Thanh Son
Using an effective field-theoretical approach, we investigate the properties of weakly bound two-neutron halo nuclei (also known as Borromean nuclei) that do not support a low-energy $s$ -wave core-neutron resonance. Extending the recently formulated effective field theory for weakly bound Borromean nuclei, we incorporate corrections arising from the effective range of neutron-neutron scattering and evaluate their impact on the mean-square radii and electromagnetic response. In particular, we compute the ratio of the matter and charge radii, the shape of the $E 1$ dipole strength function, and the electric polarizability. Our results indicate that these corrections remain numerically small when the two-neutron separation energy of the Borromean nucleus is much less than 1~MeV.
nucl-thcond-mat.quant-gashep-thPRC(2025)·4 citations
04
Relativistic $^{3}$ He light-front wave function
V.A. Karmanov🇷🇺 · Zhimin Zhu🇨🇳 · Ziqi Zhang🇨🇳 · Kaiyu Fu🇨🇳
The relativistic light-front (LF) wave function of $^{3}$ He is determined by the three-body LF equation for the Faddeev components in the momentum space. As an interaction, we take the one-meson exchange kernels, without the potential approximation. Within the explicitly covariant formulation of LF dynamics, we calculate the full relativistic $^{3}$ He LF wave function, comprising 32 spin-isospin components. In the non-relativistic domain, five of these components dominate and closely resemble their non-relativistic counterparts. Relativistic effects manifest themselves in deviations in relativistic domain of these components from the non-relativistic ones and in appearance of new components.
nucl-thhep-phJ.Subatomic Part.Cosmol.(2025)·1 citation
05
Generalized relativistic second-order dissipative hydrodynamics: coupling different rank tensors
Arus Harutyunyan🇦🇲 · Armen Sedrakian🇵🇱
In this work, we extend the formalism of second-order relativistic dissipative hydrodynamics, developed previously using Zubarev's non-equilibrium statistical operator formalism. By employing a second-order expansion of the statistical operator in terms of hydrodynamic gradients, we demonstrate that new second-order terms emerge due to the coupling of two-point quantum correlators between tensors of differing ranks, evaluated at distinct space-time points. Such terms arise because the presence of the acceleration vector in the system allows Curie's theorem, which governs symmetry constraints, to be extended for constructing invariants from tensors of different ranks evaluated at distinct space-time points. The new terms are identified in the context of a complete set of second-order equations governing the shear-stress tensor, bulk-viscous pressure, and charge-diffusion currents for a generic quantum system characterized by the energy-momentum tensor and multiple conserved charges. Additionally, we identify the transport coefficients associated with these new terms and derive the Kubo formulas expressing the second-order transport coefficients through two- and three-point correlation functions.
nucl-thastro-ph.HEhep-phAnnals Phys.(2025)·3 citations
06
Role of the $δ$ Meson in the Equation of State an Direct Urca Cooling of Neutron Stars
Luigi Scurto🇵🇹 · Helena Pais🇵🇹 · Marco Antonelli🇫🇷 · Francesca Gulminelli🇫🇷
The direct Urca (dUrca) process is a key mechanism driving rapid neutrino cooling in neutron stars, with its baryon density activation threshold determined by the microscopic model for nuclear matter. Understanding how nuclear interactions shape the dUrca threshold is essential for interpreting neutron star thermal evolution, particularly in light of recent studies on exceptionally cold objects. We investigate the impact of incorporating the scalar isovector $δ$ meson into the neutron star equation of state, which alters the internal proton fraction and consequently affects the dUrca cooling threshold. Since proton superfluidity is known to suppress dUrca rates, we also examine the interplay between the nuclear interaction mediated by the $δ$ meson and the $^{1} S_{0}$ proton pairing gap. We perform a Bayesian analysis using models built within a relativistic mean-field approximation, incorporating constraints from astrophysical observations, nuclear experiments, and known results of \textit{ab initio} calculations of pure neutron matter. We then impose a constraint on the dUrca threshold based on studies of fast-cooling neutron stars. The inclusion of $δ$ meson expands the range of possible internal compositions, directly influencing the stellar mass required for the central density to reach the dUrca threshold. Furthermore, we observe that the observation of relatively young and cold neutron stars provides insights into $^{1} S_{0}$ proton superfluidity in the core of neutron stars.
nucl-thastro-ph.HEAstron.Astrophys.(2025)·7 citations
07
Chiral Vortical Instability
Shuai Wang🇨🇳 · Koichi Hattori🇨🇳 · Xu-Guang Huang🇨🇳 · Andrey V. Sadofyev🇵🇹
We revisit the collective modes of chiral matter described by the second-order chiral hydrodynamics, noticing that chiral shear waves (CSWs) may become unstable for momenta above a characteristic scale. In the absence of sufficient dissipation, this instability emerges within the hydrodynamic regime, depending on the interplay between shear viscosity and the anomalous vortical contribution to the stress-energy tensor at second order in hydrodynamic expansion. We show that this instability generates helical flows and name it the {\it chiral vortical instability} (CVI). Alongside the chiral plasma and magnetovortical instabilities, CVI tends to transfer initial microscopic chirality into macroscopic helicities, which combine into a generalized axial charge. We further find that an elementary static Gromeka-Arnold-Beltrami-Childress flow, corresponding to a CSW at a specific momentum, solves the full nonlinear equations of second-order chiral hydrodynamics, whereas global rotation of a chiral medium is not a solution. This observation supports the relevance of CVI beyond the hydrodynamic regime. Finally, we briefly note that CVI may have multiple phenomenological implications across various systems, including QCD matter produced in heavy-ion collisions and primordial plasma in the early Universe.
↳ hep-thhep-phnucl-th3 citations
08
Correlation studies of the $^{7}$ He excited states
M. Khirk (1, 2 and 3) · L.V. Grigorenko (1, 4 and 5) · E.Yu. Nikolskii (5 and 1) · P.G. Sharov (1 and 6) ((1) Flerov Laboratory of Nuclear Reactions, JINR, Dubna, (2) M.V. Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics, Moscow, (3) MIREA - Russian Technological University, Moscow, (4) National Research Nuclear University "MEPhI'', Moscow, (5) National Research Centre "Kurchatov Institute'', Moscow, (6) Institute of Physics, Silesian University in Opava, Opava)
The unbound nucleus $^{7}$ He was recently studied in the $^{2}$ H( $^{6}$ He, $^{1}$ H) $^{7}$ He reaction at 29 $A$ MeV beam energy in Ref.[M.S. Golovkov et al., Phys. Rev. C 109, L061602 (2024)]. The excitation spectrum of $^{7}$ He was measured up to $E_{T} = 8$ MeV ( $E_{T}$ is energy above the $^{6}$ He- $n$ threshold). Angular distribution for the $^{6}$ He- $n$ decay of the $^{7}$ He $3/ 2^{-}$ ground state can be explained by a strong spin alignment induced by a reaction mechanism. The correlation information for the higher-lying $^{7}$ He excitations is available as backward-forward asymmetry for the $^{6}$ He- $n$ decay in the $^{7}$ He frame. The asymmetry function has an expressed energy profile which may be explained by using quite restrictive assumptions about structure of $^{7}$ He excitations or/and peculiarities of the reaction mechanism. In the analysis of [M.S. Golovkov et al., Phys. Rev. C 109, L061602 (2024)] the observation the $s_{1/2}$ state in $^{7}$ He is declared with $E_{r} \approx 2.0$ MeV. Our work is based on the same $^{7}$ He data. However, the data analysis was improved and also the data interpretation is substantiated with the detailed PWBA reaction studies and coupled-channel calculations of the $^{7}$ He continuous spectrum. The idea of the $s_{1/2}$ resonant state with $E_{r} \approx 2.0$ is rejected. In addition, the position of the $1/ 2^{-}$ state in $^{7}$ He is confined to the interval $E_{r} = 2.2 - 3.0$ MeV, with ``preferred'' value 2.6 MeV. There is indication on the second $3/ 2^{-}$ state in the data with $E_{r} \sim 4.5$ MeV and with the lower resonance energy limit $E_{r} ≳ 3.5$ MeV. Importance and prospects of more detailed correlation studies of $^{7}$ He continuum are discussed.
↳ nucl-exnucl-th0 citations
09
Search for doubly charmed dibaryons in baryon-baryon scattering
Yao Cui🇨🇳 · Yuheng Wu🇨🇳 · Xinmei Zhu🇨🇳 · Hongxia Huang🇨🇳 · Jialin Ping🇨🇳
We perform a systematical investigation of the doubly charmed dibaryon system with quantum numbers $I J = 01$ , and strangeness numbers $S = 0$ , $- 2$ and $- 4$ in the framework of the chiral quark model. Two resonance states with strangeness numbers $S = - 2$ is obtained in the $Λ Ω_{cc}$ scattering channel, which are $Ξ_{cc}^{*} Ξ$ with resonance mass 5081 MeV and decay width 0.3 MeV, and the $Ξ_{c} Ξ_{c}^{*}$ state with the mass 5213 MeV and decay width 19.8 MeV, respectively. These two predicted charmed dibaryon candidates are worth searching for experimentally. Besides, we would like to emphasize that the multi-channel coupling calculation is important to confirm the existence of multiquark states. The coupling can shift the energy of the resonance, give the width to the resonance and even destroy the resonance. Therefore, to provide the necessary information for experiments to search for exotic hadron states, the coupling calculation between the bound channels and open channels is indispensable.
↳ hep-phhep-exhep-latnucl-thPRD(2025)·2 citations
10
Second order fluctuations of conserved charges in external magnetic fields
Heng-Tong Ding🇨🇳 · Jin-Biao Gu🇨🇳 · Arpith Kumar🇨🇳 · Sheng-Tai Li🇨🇳
We present a first-principles lattice QCD investigation of second-order fluctuations of and correlations among conserved charges -- baryon number (B), electric charge (Q), and strangeness (S) -- in the presence of external magnetic fields. Our study employs lattice simulations of (2+1)-flavor QCD with physical pion masses using highly improved staggered fermions (HISQ) on $4 8^{3} \times 12$ and $3 2^{3} \times 8$ lattices, covering a wide range of magnetic field strengths up to $e B ≃ 0.8$ GeV $^{2}$ . We identify clear signals of magnetic field-induced modifications to these fluctuations and correlations, with the baryon-electric charge correlation, $χ_{11}^{BQ}$ , exhibiting particularly strong sensitivity to the magnetic field. To bridge theoretical predictions with experimental observables, we implement systematic kinematic cuts that emulate detector acceptances of the STAR and ALICE experiments within the hadron resonance gas (HRG) model and construct proxy observables for fluctuations measurable in heavy-ion collision experiments. Our findings highlight $χ_{11}^{BQ}$ as a promising ``magnetometer" for probing the presence of magnetic fields in QCD matter. Furthermore, we explore experimentally relevant ratios involving $χ_{11}^{BQ}$ , demonstrating their potential in mitigating volume effects and enhancing sensitivity to magnetic fields in collision environments. Additionally, we assess the limitations of the HRG model at strong magnetic fields, revealing deviations that indicate nontrivial modifications to hadronic degrees of freedom. These results offer new insights into the interplay between thermal and magnetic effects in the QCD phase diagram and provide experimentally relevant guidance for the detection of magnetic fields in heavy-ion collisions.
↳ hep-lathep-phnucl-exnucl-thPRD(2025)·20 citations
11
Femtoscopy correlation functions and hadron-hadron scattering amplitudes in presence of Coulomb potential
M. Albaladejo🇪🇸 · A. Garcia-Lorenzo🇪🇸 · J. Nieves🇪🇸
This work addresses the incorporation of Coulomb interactions into femtoscopy correlation functions (CFs) used to probe hadron interactions. Combining strong contact potentials with Coulomb effects, the derived scattering amplitudes and wave functions are used to compute CFs, accounting for both interactions coherently. Next, we analyze the nature of the corrections due to the finite range of the strong interaction, closely linked to off-shell effects, and propose an approximate method to account for them. We show how these corrections turn out to be essential to accurately extract the strong hadron-hadron scattering amplitudes from CF data. We compare the obtained expressions for the CFs with those reported in previous theoretical frameworks. Also, using proton-proton systems as a case study, we obtain a good comparison of our results with previous realistic theoretical calculations and with accurate recent data from the ALICE experiment. The framework enables precise CF calculations without numerical solution of the Schrödinger equation, offering a practical tool for femtoscopy analyses involving charged hadrons. In addition, the scheme allows for an easy connection with scattering amplitudes obtained from Effective Field Theories.
↳ hep-phnucl-thPTEP(2025)·9 citations
12
Nonperturbative Formulation of Resonances in Quantum Mechanics Based on Exact WKB Method
Okuto Morikawa🇯🇵 · Shoya Ogawa🇯🇵
We study quasi-stationary states in quantum mechanics using the exact Wentzel--Kramers--Brillouin (WKB) analysis as a nonperturbative framework. Whereas previous works focused mainly on stable systems, we explore unstable states such as resonances. As a concrete example, we analyze the inverted Rosen--Morse potential, which exhibits barrier resonance. This model allows exact solutions, enabling a direct comparison with exact WKB predictions. We provide a simple analytic picture of resonance and demonstrate consistency between exact and WKB-based results, extending the applicability of exact WKB analysis to nonpolynomial potentials.
↳ hep-thnucl-thquant-phPTEP(2025)·8 citations
13
Gravitational form factor of the kaon in holographic QCD
Zhibo Liu🇨🇳 · Akira Watanabe🇨🇳
The gravitational form factor (GFF) of the kaon is investigated in a bottom-up holographic QCD model, in which the strange quark mass breaks the SU(3) flavor symmetry. The probe energy ( $Q^{2}$ ) dependence of the kaon GFF is explicitly shown and compared to that of the pion. It is presented that our result shows the $1/ Q^{2}$ behavior in the high energy region, which is consistent with the perturbative QCD prediction. The gravitational radius of the kaon is also calculated, and it is found that the result is quite close to that of the pion but slightly smaller.
↳ hep-phnucl-thPRD(2025)·9 citations

Affiliations

first authorsco-authorsvia INSPIRE