Nuclear Theory·nucl-th

Friday·September 5, 2025

10 papers—7 primary·3 cross-listed

01
From CREX to CEvNS: The Weak Radius of 40Ar
J. Piekarewicz🇺🇸
Despite significant theoretical efforts, the CREX-PREX dilemma remains unresolved, preventing the reliable prediction of neutron (or weak-charge) radii that, besides their intrinsic nuclear-structure interest, often serve to quantify the impact of nuclear uncertainties in searches for new physics. Coherent elastic neutrino-nucleus scattering is a clean and attractive portal to new physics whose sensitivity may be impacted by such nuclear uncertainties. In this paper we use CREX as our main anchor, together with a strong calcium-argon correlation, to provide a robust baseline for the weak radius of $^{40}$ Ar: $R_{wk}^{40} = 3.452 \pm 0.028 (stat) \pm 0.022 (syst) fm$ .The weak radius of argon is an observable highly relevant to ongoing and future liquid-argon campaigns that encodes the loss of coherence at small momentum transfers.
nucl-thhep-exhep-thnucl-exPRC(2025)·4 citations
02
Light nuclei under magnetic field and the lithium problem
Nodoka Yamanaka
We analyze the effect of the magnetic field on the proton and neutron density distributions of the nuclei 2H, 3H, 3He, which are calculated ab initio, and the 6Li nucleus in the alpha-cluster model. It is found that the asymptotic exponential damp of the probability density at long distance is modified, and that the linear component of the exponent with respect to the magnetic field yields the leading contribution, while those of the second derivative and the confining magnetic force are subleading. Due to the linear dependence of the exponent, fluctuating magnetic fields always enhance the tunneling rate, i.e. the cross section of low energy nuclear reactions which occur at large separation across the Coulomb barrier. While this mechanism cannot suppress the production of 7Be in the early Universe, it has the potential to resolve the lithium problem either by increasing the reaction rate of 7Be + p -> 8B at the bigbang nucleosynthesis era if the magnetic field at this time was sufficiently strong, or by correcting the systematically enlarged 4He + 3He -> 7Be cross section by the unwanted magnetic field generated in the nuclear experimental setup, which was so far used as the input of the simulation of bigbang nucleosynthesis.
nucl-thastro-ph.COhep-phnucl-ex2 citations
03
Mechanism of the quasi-elastic scattering based on the dinuclear system concept
Zehong Liao · Yu Yang · Zepeng Gao · Jun Su · Long Zhu
A unified description of full reaction channels in low-energy heavy-ion collisions is a great challenge. Although the theoretical models based on the dinuclear system (DNS) concept have been successfully employed in multinucleon transfer (MNT) reactions, the underestimation of the quasi-elastic (QE) channel results in unreliable description of few nucleon transfer, especially for the light reaction systems. In this work, the DNS-sysu model is improved by introducing the impact-parameter-dependent transition probabilities for a unified description of few nucleon and many nucleon transfer in MNT reactions. Extensive experimental data -- including reactions such as 40Ca, 58Ni, 64Ni, 136Xe, and 208Pb + 208Pb -- were compared with the model predictions. The calculated isotopic distributions, mass distributions, and charge distributions show good agreement with experimental measurements. The improved DNS-sysu model enables reasonable characterization and description of the QE/grazing collisions, notably resolving long-standing underestimation in the QE channel.
nucl-thPRC(2025)·1 citation
04
Exploring the fluid behavior in p+p collisions at $s = 13 TeV$ with viscous anisotropic hydrodynamics
Shujun Zhao🇨🇳 · Yiyang Peng🇨🇳 · Ulrich W. Heinz🇺🇸 · Huichao Song🇨🇳
The applicability of hydrodynamics in small collision systems remains controversial due to the small size and short lifetime of the system. In this letter, we employ viscous anisotropic hydrodynamics (VAH), which incorporates large pressure anisotropies, to study the collectivity in p+p collisions at $s = 13 TeV$ .VAH provides a good description for $v_{2} {2}$ and $v_{3} {2}$ over a wide range of multiplicities and correctly reproduces the experimentally observed negative $c_{2} {4}$ . Traditional second-order viscous hydrodynamics (VH), on the other hand, can describe the measurements, in particular the negative $c_{2} {4}$ , only with model parameters for which the bulk of the evolution is characterized by large values of the shear Knudsen number. It also can not capture the large longitudinal/transverse pressure anisotropy during the early evolution. These demonstrate the failure of traditional viscous hydrodynamics in small collision systems and establish viscous anisotropic hydrodynamics as a more reliable framework to describe the bulk evolution and the observed anisotropic flow in p-p collisions at the LHC.
nucl-thhep-phnucl-exPRL(2026)·2 citations
05
Neutrino absorption in two-flavor color-superconducting quark matter
Mark G. Alford🇺🇸 · Liam Brodie🇺🇸 · Michael Buballa🇩🇪 · Hosein Gholami🇩🇪 · Alexander Haber🇺🇸 · Marco Hofmann🇺🇸
We calculate the absorption mean free paths of electron and muon neutrinos in two-flavor color-superconducting (2SC) quark matter in the density and temperature range that is relevant to binary neutron star mergers. We model the strong interaction between quarks using a Nambu--Jona-Lasinio model, performing calculations self-consistently in the mean-field approximation. Since the 2SC gap is large we restrict our analysis to the contribution of unpaired quarks. We find that at low temperatures absorption by a down quark $ν + d \to u + e^{-} / μ^{-}$ is kinematically not allowed, so absorption by a strange quark $ν + s \to u + e^{-} / μ^{-}$ dominates the mean free path. As temperature or neutrino energy rises, the $d$ quark absorption channel becomes active, and the mean free path shrinks. We find that in equilibrated 2SC matter with an electron lepton fraction $Y_{L_{e}} = 0.1$ , the neutrinos form a degenerate gas with a mean free path of meters or less, independent of the temperature.
nucl-thastro-ph.HEhep-ph12 citations
06
Three models for charged hadron nuclear modification from light to heavy ions
Wilke van der Schee🇨🇭 · Isobel Kolbé🇿🇦 · Govert Nijs🇨🇭 · Kumail Ruhani🇵🇰 · Ishtiaq Ahmed🇵🇰 · Shahin Iqbal🇵🇰
In July 2025 the Large Hadron Collider (LHC) collided $^{16}$ O $^{16}$ O and $^{20}$ Ne $^{20}$ Ne isotopes in a quest to understand the physics of ultrarelativistic light ion collisions. One of the key motivations for this run is to discover partonic energy loss in systems with a small quark-gluon plasma (QGP). In this letter we combine a BDMPS-Z based model, a path-length based energy loss prescription, and JEWEL together with two realistic geometries of the $^{16}$ O and $^{20}$ Ne isotopes. The different sizes of the ions affect the energy loss in characteristically different ways depending on the model.
nucl-thhep-phnucl-ex15 citations
07
Extended applicability domain of viscous anisotropic hydrodynamics in (2+1)-D Bjorken flow with transverse expansion
Yiyang Peng🇨🇳 · Victor E. Ambrus🇷🇴 · Clemens Werthmann🇧🇪 · Sören Schlichting🇩🇪 · Ulrich Heinz🇺🇸 · Huichao Song🇨🇳
We perform (2+1)-D simulations of viscous anisotropic hydrodynamics (VAH) under boost-invariant and conformal conditions. Comparing both VAH and traditional viscous hydrodynamics with kinetic theory in the relaxation-time approximation as the underlying microscopic theory, we show that VAH provides a superior description of the evolution across a wide range of opacity, effectively extending the applicability of hydrodynamic modeling. Our results demonstrate VAH's potential for describing collective flow in small systems where traditional hydrodynamics faces challenges.
nucl-thhep-thPRC(2026)·0 citations
08
Strong CP Violation and large- $N_{c}$ spin-flavor symmetry
Thomas R. Richardson🇺🇸
We revisit the contribution of the QCD $θ ˉ$ term to the CP violating pion-nucleon couplings and the nucleon electric dipole moment in a combined large- $N_{c}$ and chiral perturbation theory framework. In particular, we approach this issue through the emergent spin-flavor symmetry of the baryon sector at large but finite $N_{c}$ . We obtain good agreement with previous analyses for the pion-nucleon couplings and show that the large- $N_{c}$ framework indicates that tree-level contributions to the electric dipole moment possibly play a dominant role. The spin-flavor symmetry also enables us to provide novel constraints on CP violating pion- $Δ$ couplings as well as the $Δ$ electric dipole moment and $Δ N$ transition moment.
↳ hep-phhep-latnucl-thPRD(2025)·3 citations
09
Stability analysis of two-fluid neutron stars featuring twin star and ultradense configurations
Ankit Kumar🇯🇵 · Hajime Sotani🇯🇵
We perform a detailed analysis of radial oscillations to discuss dynamical stability in two-fluid neutron stars composed of ordinary nuclear matter and a gravitationally coupled dark matter component. Using a fully relativistic two-fluid formalism, we solve the eigenvalue problem for a coupled system of equations with small-amplitude radial perturbations and derive the critical line corresponding to stability boundaries. We also compare these stability boundary lines obtained from the radial perturbations with those obtained from a generalized turning-point criterion based on extremization of mass and particle numbers, and find that the two methods agree to within better than $1%$ across the parameter space explored. We consider both mirror dark matter and self-interacting fermionic dark matter models, and examine how microphysical properties $-$ such as nuclear equations of state, dark matter mass, and vector coupling strength $-$ reshape the topology of the stability boundary and gravitational mass contours. Our results reveal the emergence of ultra-dense and compact stars, with nuclear central densities exceeding single-fluid instability thresholds by factors of two or more, and the appearance of twin-star configurations with identical masses but distinct radii and internal fluid compositions. These findings have direct implications for the interpretation of neutron star observables and motivate future studies involving phase transitions, density discontinuities, or additional interactions in multi-component stellar systems. In particular, the emergence of exotic stable configurations beyond conventional stability limits underscores the need to reassess standard criteria in light of multi-fluid dynamics, with significant consequences for multimessenger probes of dense matter $-$ including gravitational wave signals, mass-radius constraints, and post-merger remnants.
↳ astro-ph.HEhep-thnucl-thPRD(2025)·10 citations
10
Jet broadening and radiation in the early anisotropic plasma in heavy-ion collisions
Alois Altenburger🇦🇹 · Kirill Boguslavski🇦🇹 · Florian Lindenbauer🇦🇹
Measuring the energy loss of energetic jet partons may provide experimental opportunities to constrain the initial nonequilibrium stages in heavy-ion collisions, which requires theoretical predictions for the jet-medium potential. In this letter, we go beyond the usual harmonic approximation, extract this potential for the first time using QCD kinetic theory simulations, and provide a simple cutoff-independent small-distance form. We find significant differences to thermal media at early times in momentum and position space, as well as substantial angular dependence. Applying our results to the gluon splitting rates using a novel computational method reveals tensions in the current kinetic theory implementations for early times.
↳ hep-phnucl-th14 citations

Affiliations

first authorsco-authorsvia INSPIRE