Nuclear Theory·nucl-th

Tuesday·March 3, 2026

19 papers—11 primary·8 cross-listed

01
[Submitted on 27 Feb 2026]
Spin-2 Mesons in a Relativistic Hartree Description of Nuclei
Brendan T. Reed🇺🇸 · Marc Salinas🇺🇸
The role of the isovector spin-orbit potential in nuclear modeling has recently been explored in greater detail due largely in part to the PREX and CREX parity violating electron scattering (PVES) experiments. The result of both experiments have shown that the neutron-rich skins of $^{48}$ Ca and $^{208}$ Pb, as determined by the experimental analysis, are largely incompatible with current nuclear model predictions. One way to address, and potentially solve, this incompatibility has been to enhance the isovector spin-orbit sector of density functional models. Here, we explore the range of possible enhancements in the context of covariant density functional theory by introducing a new class of spin-2 \textit{massive} mesons to the Lagrangian. In doing so, we find that these mesons not only meaningfully contribute to the theory, but also mitigate problems seen in other works which enhance spin-orbit effects in finite nuclei. We also discuss the implications and future regarding this ``dilemma'' as it pertains to studies of nuclear forces and future experiments such as the Mainz Radius Experiment (MREX).
Comments:
12 pages of article, 9 pages of appendix derivations, 8 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2603.00274 [pdf]
0 citations
02
[Submitted on 27 Feb 2026]
Electromagnetic Properties of the N=50 Isotones with the p35-i3 Hamiltonian
J. A. Purcell · B. A. Brown
The nuclei with 50 neutrons that lie between $^{78}$ Ni and $^{100}$ Sn have provided benchmark studies of the nuclear shell model for protons in the ${0 f_{5/2}, 1 p_{3/2}, 1 p_{1/2}, 0 g_{9/2}}$ model space. New Hamiltonians for this model space have recently been obtained based on valence-space in-medium renormalization-group (VS-IMSRG) methods with two- and three-nucleon interactions. The two-body matrix elements (TBME) obtained from these ab-initio methods served as the starting point for singular-value decomposition (SVD) method fits of the TBME to experimental binding energies and excitation energies, resulting in Hamiltonians called p35-i2, p35-i3 and p30-i3. In this paper, magnetic moments, quadrupole moments, $B (M 1)$ and $B (E 2)$ values obtained with these Hamiltonians are presented and compared to experiment. Results obtained from various Hamiltonians are compared to assess the theoretical uncertainties.
Comments:
12 pages, 17 figures, 4 tables, submitted to Phys. Rev. C
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2603.00352 [pdf]
PRC(2026)·0 citations
03
[Submitted on 27 Feb 2026]
Relativistic Effects in Femtoscopy and Deuteron Formation
Stanislaw Mrowczynski
For a long time studies of femtoscopic correlations have provided information about space-time characteristics of particle sources in high-energy collisions. Recently, the correlation functions have been also used to determine interaction parameters of correlated particles which is especially important for short-lived particles, for which scattering experiment are impossible. The abundance of experimental data and their high accuracy require an improved theoretical approach to femtoscopic correlations. We discuss relativistic effects and their role in detail. Since a general relativistic approach is currently unavailable, due to serious theoretical difficulties, the correlation functions must be computed in the center-of-mass frame where the correlated particles are mostly nonrelativistic. This requires transforming the source function to this frame, the consequences of which we discuss. Since the deutron formation has a similar physical origin to femtoscopic correlations, we also discuss relativistic effects in the former process. We illustrate our considerations with calculations of some correlation functions and the deuteron coalescence coefficient to demonstrate a magnitude of relativistic effects. We also argue that a discrepancy between the coalescence coefficient computed with the source radii inferred from the baryon-baryon correlation functions and the experimental data can be removed by taking into account the relativistic elongation of the source radius in the center of mass of correlated particles.
Comments:
17 pages, 4 figures, Phys. Rev. C in print
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2603.00354 [pdf]
0 citations
04
[Submitted on 1 Mar 2026]
Angular momentum conservation and pion production in intermediate-energy heavy-ion collisions
Hao-Nan Liu🇨🇳 · Rong-Jun Liu🇨🇳 · Jun Xu🇨🇳
We have studied the effect of rigorous angular momentum conservation (AMC) in elastic, inelastic, and decay channels on pion production in intermediate-energy heavy-ion collisions based on the framework of an isospin-dependent Boltzmann-Uehling-Uhlenbeck (IBUU) transport model. We found that the constraint of AMC suppresses the absorption of both $Δ$ resonances and pions, thus considerably enhances pion production and meanwhile reduces the charged pion yield ratio. The AMC effect on the charged pion yield ratio can not be simply compensated by a density-dependent in-medium $Δ$ production cross section. Therefore, incorporating the constraint of AMC is important in obtaining the correct pion multiplicity and charged pion yield ratio by transport simulations, relevant for the extraction of the nuclear symmetry energy at high densities.
Comments:
7 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2603.00865 [pdf]
PLB(2026)·0 citations
05
[Submitted on 1 Mar 2026]
QCD phase transition at finite isospin density and magnetic field
Chujun Ke🇨🇳 · Gaoqing Cao🇨🇳
The QCD phase transition is explored at finite isospin density and magnetic field within the extended two-flavor Nambu--Jona-Lasinio model. By adopting the Ginzburg-Landau approximation, we study the transitions from normal chiral symmetry breaking phase to pion superfluidity or rho superconductivity. To avoid the artificial divergence for a large isospin chemical potential, we adopt the Landau representation rather than the proper-time one for the fermion propagators in a constant magnetic field. For the Landau representation, the same cutoff to the Landau energies, rather than to Landau levels, should be adopted to regularize the divergences from the summations over Landau levels. Then, the Ginzburg-Landau coefficients for pion and rho mesons are worked out both analytically and numerically in random phase approximation. The results show that pion superfluidity is favored for a small magnetic field while rho superconductivity is favored for a large magnetic field when increasing isospin chemical potential, in line with the magnetic enhancement (deduction) of the lowest energy of $π^{+} (ρ^{+})$ meson. The novel rho superconductivity phase at large magnetic field and finite isospin density implies an interesting and nontrivial interplay between QCD and QED.
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2603.01061 [pdf]
1 citation
06
[Submitted on 2 Mar 2026]
Auxiliary counterterms and their role in effective field theory
Manuel Pavon Valderrama🇨🇳
Effective field theories include contact-range interactions (or counterterms) for two reasons: representing the unknown short-range physics in a model independent manner and ensuring the cutoff independence of observables. Both are intertwined: cutoff independence alone (modulo truncation errors) already generates counterterms encoding physical information not present in the known long-range physics. Yet, there is also residual cutoff dependence, which is smaller than the uncertainties that are achievable within the effective field theory description and thus can be safely neglected in most settings. If one insists on exact cutoff independence though, new counterterms will be required, but they encode no new physical information and are thus what one could call redundant, or auxiliary, counterterms. It happens that auxiliary counterterms are still useful for solving certain inconsistencies that appear during renormalization or for improving the convergence of the effective field theory expansion. Examples of these use cases are discussed, including the interpretation of the improved actions or the relation between perturbative and non-perturbative renormalization.
Comments:
19 pages, corresponds with published version
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2603.01561 [pdf]
EPJA(2026)·2 citations
07
[Submitted on 2 Mar 2026]
Sensitivity of Isotopic Fission Yields in Actinides to the Macroscopic Liquid-Drop Model: LSD vs ISOLDA
K. Pomorski · A. Augustyn · T. Cap · Y. J. Chen · M. Kowal · B. Nerlo-Pomorska · M. Warda · Z. G. Xiao
The impact of the macroscopic liquid-drop prescription on isotope-resolved fission-fragment yields in the actinide region is assessed by comparing two alternative parameterizations: the Lublin--Strasbourg Drop (LSD) model and the ISOscalar Liquid Drop Approximation (ISOLDA). The two prescriptions differ primarily in the treatment of isospin dependence in the volume and surface terms; in ISOLDA, an explicit dependence on the isospin square $T (T + 1)$ , where $T = ∣ N - Z ∣/2$ , is introduced in both coefficients. Using an identical set of fragment-yield observables and the same experimental reference (fission of $^{250}$ Cf $^{*}$ at low and high energies), the propagation of the macroscopic-energy choice into the predicted yields is quantified in terms of (i) the location of the most probable post-neutron isotopes along elemental chains, (ii) the widths and asymmetries of the isotopic distributions, and (iii) the population of neighboring nuclides on the distribution tails. A comparable description of the gross properties of the isotopic yield pattern is obtained with both prescriptions, particularly for light and intermediate fragments, where peak positions and near-maximum curvatures are reproduced similarly. The most discriminating differences are found for heavy-fragment chains, for which the ridge location and isotopic centroids are rendered more sensitive to macroscopic isospin terms. Overall, a closer average agreement with the evaluated data is obtained with LSD, while the LSD--ISOLDA spread is shown to provide a practical estimate of the macroscopic-model uncertainty in isotope-resolved yields.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2603.01794 [pdf]
0 citations
08
[Submitted on 2 Mar 2026]
Recent developments and applications of the relativistic chiral nuclear force
Li-Sheng Geng🇨🇳 · Jun-Xu Lu🇨🇳 · Qing-Yu Zhai🇨🇳 · Zhi-Wei Liu🇨🇳 · Shihang Shen🇨🇳
The nuclear force is central to our understanding of complex nuclear phenomena and to the applications of nuclear techniques. The nonperturbative nature of the low-energy strong interaction and the color confinement have made an ab initio understanding of the nuclear force a challenge for almost a century since the pioneering work of Yukawa. Since 1990, chiral effective field theory (ChEFT) has become the de facto standard for describing nuclear interactions--most prior studies employed heavy-baryon chiral perturbation theory. Only recently, there have been successful attempts to construct a chiral nuclear force employing covariant baryon chiral perturbation theory. In this work, we review recent developments and applications of relativistic chiral nuclear forces. We first elaborate on the necessity of relativistic/covariant theories, then present the construction of the first high-precision relativistic chiral nuclear force up to next-to-next-to-leading order (NNLO), and discuss the ongoing progress in higher-order nucleon-nucleon (NN) and $n d$ scattering, as well as their applications in nuclear matter, finite nuclei, and hypernuclear systems. Finally, we summarize the achievements and outline the future outlook of this research field.
Comments:
24 pages, 14 figures, plenary talk given by Li-Sheng Geng at the International Symposium Commemorating the 40th Anniversary of the Halo Nuclei (HALO-40)
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2603.01819 [pdf]
Particles(2026)·1 citation
09
[Submitted on 2 Mar 2026]
Hadronic description of nuclear matter and neutron star properties
Yao Ma🇨🇳 · Yong-Liang Ma🇨🇳 · Jia-Ying Xiong🇨🇳
The composition of the neutron star is one of the most fundamental and long-standing problems in nuclear- and astro-physics. The known properties of nuclear matter, together with the astronomical observations, impose the stringent and interconnected constraints on the theoretical descriptions. In this work, by using the most general quantum hadrodynamics model including $σ, ω, ρ$ and $a_{0}$ in addition to nucleons, and performing a Bayesian joint analysis of experimental nuclear matter data and astrophysical observations, we point out that the nuclear matter made of only hadrons can provide a unified description of nuclear matter properties and astrophysical observations at $1 σ$ -level. In addition, we find that the existence of $\sigma\omega\rho a_0$ interaction naturally leads to a peak structure in the speed of sound at $\sim (2 - 3)$ times saturation density $n_{0}$ which results to a small size intermediate mass neutron star and the upper bound mass $\sim 2 M_{⊙}$ . What we find here indicate that the sequential measurement of neutron star mass and radius by the next generation facilities, especially that of the intermediate mass neutron stars, is crucial for distinguishing the pure nucleonic stars from the hybrid ones.
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2603.01933 [pdf]
3 citations
10
[Submitted on 2 Mar 2026]
Explicit asymptotics of coupling matrix elements for central potentials in the hyperspherical harmonics expansion method
Emile Meoto · Mantile L. Lekala
The analytic structure and asymptotic behavior of channel-coupling potentials in three-body systems are investigated within the framework of the hyperspherical harmonics expansion method. The coupling between different Jacobi partitions is expressed using Raynal--Revai transformation coefficients and a reduced hyperangular integral that contains the two-body interaction. For central potentials, this integral is factorised into geometric and dynamical components. Explicit asymptotic scaling laws are derived for the hyperradial coupling strength in the limit of large hyperradius $ρ \to \infty$ for representative nuclear potentials: Gaussian, Yukawa, and Woods--Saxon potentials (short-range), and Coulomb potential (long-range). These short-range potentials are found to exhibit an algebraic decay $\propto ρ^{- (2 ℓ_{η_{i}} + 3)}$ , where $ℓ_{η_{i}}$ is the orbital angular momentum of the interacting pair. This decay is shown to lead to efficient asymptotic decoupling of hyperspherical channels. In contrast, the Coulomb interaction yields couplings that decay only as $1/ ρ$ , indicating persistent channel coupling at large distances and explaining the slow convergence of hyperspherical expansions for charged systems. These results provide a quantitative basis for truncating the hyperradial domain, for example, in choosing a matching radius for scattering calculations or an upper integration limit in bound-state problems.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2603.02020 [pdf]
NPA(2026)·0 citations
11
[Submitted on 2 Mar 2026]
Spinodal instability in nuclear matter with light cluster degrees of freedom
Stefano Burrello🇮🇹 · Carmelo Piazza🇮🇹 · Rui Wang🇮🇹 · Maria Colonna🇮🇹
We investigate the thermodynamical stability of low-density isospin-symmetric nuclear matter at finite temperature, explicitly including light clusters as degrees of freedom. Within a generalized mean-field framework, we compute the curvature matrix of the free-energy density and determine the spinodal region, identifying the conditions under which mechanically unstable modes may develop in the presence of clustering. Particular attention is devoted to the formal consequences of introducing an infrared momentum cutoff in the density and current moments, which effectively accounts for Pauli-blocking effects and the associated reduction of low-momentum quasiparticle states in the medium. We show that when the cutoff is density dependent, thermodynamic consistency requires additional contributions to the chemical potentials and extra terms also appear in the first hydrodynamic moment, influencing both the stability analysis and the location of the spinodal boundary. We further examine the character of the unstable modes and find that a sufficiently stiff density dependence of the cutoff may drive clusters to fluctuate out of phase with nucleons, pushing them toward low-density regions while nucleonic instabilities grow, in contrast with the in-phase pattern obtained when in-medium effects are neglected. Our results shed new light on the role of light clusters in the phase dynamics of warm, dilute nuclear matter, with implications for heavy-ion collisions and for the physics of neutron-star crusts.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2603.02060 [pdf]
PRC(2026)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE