Nuclear Theory·nucl-th

Tuesday·December 31, 2024

23 papers—8 primary·15 cross-listed

01
QCD sum rule approach to Okamoto-Nolen-Schiffer anomaly
Hiroyuki Sagawa🇯🇵 · Tomoya Naito🇯🇵 · Xavier Roca-Maza🇪🇸 · Tetsuo Hatsuda🇯🇵
A new framework is introduced to connect between a charge symmetry breaking (CSB) energy density functional (EDF) and the low-energy constants derived from quantum chromodynamics (QCD). By constructing a QCD-based CSB EDF, this method provides new insights into the Okamoto-Nolen-Schiffer anomaly, a long-standing puzzle in the energy differences of mirror nuclei that lacks a robust microscopic explanation. Using examples such as $^{17} F$ - $^{17} O$ , $^{15} O$ - $^{15} N$ , $^{41} Sc$ - $^{41} Ca$ , and $^{39} Ca$ - $^{39} K$ , we demonstrate that the proposed interaction effectively resolves the anomaly within the range of theoretical uncertainties.
nucl-thnucl-exPoS(2025)·0 citations
02
Constituent Quark Model and nucleon-Nucleon Potentials
Th. A. Rijken🇳🇱
In these notes, while focusing on the meson-nucleon vertices, we give a derivation of the nucleon-nucleon 9NN) potentials from meson-exchange between quarks. To establish such a relation the quark-quark-meson (QQM) interactions are properly defined. Hitherto, the coefficients in the Pauli-spinor expansion of the meson-nucleon-nucleon (NNM) vertices are equated with those of the QQM-vertices. In these notes we employ the description of the nucleon with Dirac-spinors in the SU(6) semi-relativistic "constituent" quark-model (CQM) as formulated by LeYouanc, et al. It appears that the constituent quark model with $m_{q} = M_{N} /3$ , is able to produce the same ratio's for the central-, spin-spin-, tensor-, spin-orbit-, and quadratic-spin-orbit Pauli-invariants as in the phenomenological NNM-vertices. In order to achieve this, the scalar-, magnetic-vector, and axial-vector interactions require, besides the standard ones, an extra coupling to the quarks without the introduction of new parameters. in the case of the axial-vector mesons an extra coupling to the quarks is necessary, which is related to the quark orbital angular momentum contribution to the nucleon spin. Furthermore, a momentum correlation between the quark that is coupled to the meson and the remaining quark pair, and a (gaussian) QQM form factor, are necessary to avoid "spurious" terms. From these results we have obtained a formulation of the QQ-interactions which is directly related to the NN extended-soft-core (ESC) interactions. This has been applied to mixed quark-nuclear matter in a study of (heavy) neutron stars.
nucl-thhep-ph2 citations
03
Stiffening of matter in quark-hadron continuity: a mini-review
Toru Kojo🇯🇵
Recent observations of neutron stars, combined with causality, thermodynamic stability, and nuclear constraints, indicate a rapid stiffening of QCD matter at densities slightly above nuclear saturation density ( $n_{0} ≃ 0.16 fm^{- 3}$ ). The evolution of the stiffening is faster than expected from purely nucleonic models with many-body repulsion. Taking into account the quark substructure of baryons, we argue that the saturation of quark states occurs at $\sim$ 2-3 $n_{0}$ , driving quark matter formation even before baryonic cores of radius $\sim$ 0.5 fm spatially overlap. We describe the continuous transitions from hadronic to quark matter within a quarkyonic matter model in which gluons are assumed to remain confining at densities of interest. To obtain analytic insight into the transient regime, we construct an ideal model of quarkyonic matter, the {\it IdylliQ} model, in which one can freely switch from baryonic to quark descriptions and vice versa.
nucl-thastro-ph.HEhep-phJ.Subatomic Part.Cosmol.(2025)·12 citations
04
Transport coefficients of dense nucleon matter at low temperature
Jianing Li🇨🇳 · Weiyao Ke🇨🇳
The transport property of cold and dense nucleon matter is important for nuclear physics but is relatively less studied than that at finite temperatures. In this paper, we present a primary study of bulk and shear viscosities in the limit $T / μ_{B} ≪ 1$ , where $T$ and $μ_{B}$ are the temperature and the baryon chemical potential. The analysis is performed for a generic system where nucleons are dressed by the condensation of both scalar and vector interactions. Under the relaxation time approximation of the Boltzmann equation, we compute the viscosities of the system to leading power in $T / μ_{B}$ expansion and establish a relation between the thermodynamic potential and transport coefficients, including bulk viscosity ( $ζ$ ) and shear viscosity ( $η$ ). It is found that hydrodynamic stability ( $ζ > 0$ ) imposes additional constraints on the thermodynamic potential. As an example, these relations are applied to the Walecka model. The fluid properties of the cold and dense nucleon matter are characterized by the dimensionless combination of viscosities times the quasi-Fermi momentum over the enthalpy. Furthermore, we discuss the implication of the stability condition on the range of applicability of the model.
nucl-thcond-mat.str-elhep-phhep-thPRC(2025)·1 citation
05
Dipole response of deformed halo nuclei $^{31}$ Ne and $^{37}$ Mg
Xiao Lu · Hiroyuki Sagawa · Shan-Gui Zhou
We study the soft electric dipole ( $E 1$ ) response of deformed halo nuclei $^{31}$ Ne and $^{37}$ Mg using a deformed Woods-Saxon potential, with the potential depth adjusted to reproduce empirical separation energy of last neutron orbit, i.e., 150 keV for $^{31}$ Ne and 220 keV for $^{37}$ Mg. The configuration dependence of the $E 1$ strength near the neutron threshold is pointed out. The halo configurations $[321] 3/2$ at $β_{2} = 0.5$ and $[330] 1/2$ at $β_{2} = 0.24$ in $^{31}$ Ne contain large amplitudes of halo $p$ -shell orbits, which significantly enhance the threshold strength by several times compared to the non-halo configuration $[202] 5/2$ at $β_{2} = 0.32$ . In $^{37}$ Mg, the last neutron configuration is assigned as $[321] 1/2$ at a large deformation of $β_{2} = 0.46$ , which involves a halo $p$ -shell configuration that significantly enhances the soft dipole strength. This enhancement is about 60\% larger than that of the $[321] 3/2$ configuration in $^{31}$ Ne because of large $p$ -shell probability in $^{37}$ Mg. Experimental confirmation of the soft dipole strength is highly desired to determine the deformation and the configuration of the last neutron orbits both in $^{31}$ Ne and $^{37}$ Mg.
nucl-thPRC(2025)·5 citations
06
Machine learning orbital-free density functional theory: taming quantum shell effects in deformed nuclei
X. H. Wu · Z. X. Ren · P. W. Zhao
Accurate description of deformed atomic nuclei by the orbital-free density functional theory has been a longstanding textbook challenge, due to the difficulty in accounting for the intricate quantum shell effects that are present in such systems. Orbital-free density functional theory is, in principle, capable of describing all effects of nuclear systems, as guaranteed by the Hohenberg-Kohn theorem. However, from a microscopic perspective, shell and deformation effects are believed to be intrinsically connected to single-orbital structures, posing a significant challenge for orbital-free approaches. Here, we develop a machine learning approach to the orbital-free density functional theory, which is capable of achieving a high level of accuracy in describing the ground-state properties and potential energy curves for both spherical $^{16}$ O and deformed $^{20}$ Ne nuclei. This is the inaugural instance where a fully orbital-free energy density functional has succeeded in taming the complex shell effects in deformed nuclei. It demonstrates that the orbital-free energy density functional, which is directly based on the Hohenberg-Kohn theorem, is not only a theoretical concept but also a practical one for nuclear systems.
nucl-thnucl-exquant-phCommun.Phys.(2025)·11 citations
07
The reduced-width amplitude in nuclear cluster physics
De-Ye Tao · Bo Zhou
The reduced-width amplitude, as a cluster overlap amplitude, is one important physical quantity for analyzing clustering in the nucleus depending on specified channels and has been calculated and applied widely in nuclear cluster physics. In this review, we briefly revisit the theoretical framework for calculating the reduced-width amplitude, as well as the outlines of cluster models to obtain the microscopic or semi-microscopic cluster wave functions. Besides, we also introduce recent progress related to the cluster overlap amplitudes, such as implementation for cross-section estimation and extension to three-body clustering analysis. Comprehensive examples are provided to show the applications of the reduced-width amplitude in analyzing cluster structures.
nucl-thNucl.Sci.Tech.(2025)·10 citations
08
Effects of asymmetric dark matter on a magnetized neutron star: A two-fluid approach
Pinku Routaray🇮🇳 · Vishal Parmar🇮🇹 · H. C. Das🇮🇹 · Bharat Kumar🇮🇳 · G. F. Burgio🇮🇹 · H.-J. Schulze🇮🇹
We study the interaction between dark matter (DM) and highly magnetized neutron stars (NSs), focusing on how DM particle mass, mass fraction, and magnetic field (MF) strength affect NS structure and stability. We consider self-interacting, nonannihilating, asymmetric fermionic DM that couples to NSs only through gravitational interaction. Using the Quantum Monte Carlo Relativistic Mean Field (QMC-RMF4) model with density-dependent magnetic fields, we investigate the magnetized equation of state and examine the accumulation of DM under various conditions. Our results show that as the DM fraction increases, the maximum gravitational mass of the NS decreases, especially for heavier DM particles, while lighter DM particles can induce a transition from a dark core to a halo structure, increasing the maximum mass. Strong MFs soften the equation of state and reduce the dark mass a NS core can retain before transitioning to a halo. By comparing our results with observations from Neutro Star Interior Composition Explorer and GW170817, we identify the possible range of DM parameters for these objects. We find that the magnetic field slightly changes these limits, mainly affecting the maximum NS mass and tidal deformability. These findings provide key insights into how DM and MF jointly shape the mass-radius relation and the stability of DM-admixed magnetized NSs.
nucl-thastro-ph.HEgr-qchep-phPRD(2025)·14 citations

Affiliations

first authorsco-authorsvia INSPIRE