Nuclear Theory·nucl-th

Wednesday·January 28, 2026

17 papers—11 primary·6 cross-listed

01
[Submitted on 26 Jan 2026]
Partial-wave decomposition of isospin-projected subleading three-nucleon contact interactions
Elena Filandri🇮🇹 · Luca Girlanda🇮🇹 · Ylenia Capitani🇮🇹
We analyze the subleading three-nucleon contact interaction terms at N4LO in chiral effective field theory. We perform the isospin projection into $T = 1/2$ and $T = 3/2$ states, and find that only eleven of the thirteen operators contribute in the $T = 1/2$ channel. By projection on the partial waves of the asymptotic configuration of $N - d$ scattering states in momentum space, we find contributions from ten combinations of LECs. These results provide a useful basis for including N4LO three-body forces in few-body calculations and for constraining them through numerical fits to data.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2601.19033 [pdf]
2 citations
02
[Submitted on 27 Jan 2026]
Green's Function Formalism for Impurity-Induced Resonances in Sub-barrier Proton-Nucleus Scattering
Bahruz Suleymanli🇹🇷 · Kutsal Bozkurt🇫🇷
Motivated by recent experimental refinements of stellar reaction rates, we establish a non-perturbative Green's function formalism based on the exact solution of the Dyson equation for sub-barrier proton-nucleus resonant scattering. By utilizing bare Green's functions to map the quantum tunneling problem onto a scattering formalism, we demonstrate that the summation of infinite quantum paths recovers the exact tunneling coefficients, enabling an analytical solution of the Dyson equation where the strong nuclear force is modeled as a surface delta-shell impurity embedded within the Coulomb field. Applying this framework to the astrophysically relevant $p +^{7} Li$ , $p +^{14} N$ , and $p +^{23} Na$ systems, we achieve precise agreement with experimental resonance energies while revealing a fundamental physical distinction in resonance formation. The heavier $^{23} Na$ system is identified as a saturated state, residing on a geometric plateau where the resonance energy becomes insensitive to the interaction strength; our calculated value of $2.11$ ~MeV aligns remarkably well with the experimental level of $2.08$ ~MeV. In contrast, the lighter $^{7} Li$ and $^{14} N$ systems emerge as threshold states in a weak-coupling window, where the resonance energy is highly sensitive to the potential parameters and is sustained near the continuum edge. In this regime, our model yields energies of $0.489$ ~MeV and $1.067$ ~MeV, closely reproducing the experimental benchmarks of $0.441$ ~MeV and $1.058$ ~MeV, respectively. We demonstrate that these threshold states are characterized by a significant enhancement of the resonant cross-section, driven by the inverse relationship between the tunneling width and the spectral density peak.
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Experiment (nucl-ex)
arXiv:
2601.19374 [pdf]
NPA(2026)·1 citation
03
[Submitted on 27 Jan 2026]
Short-distance production of three particles with large scattering length
Timothy G. Backert🇩🇪 · Sebastian Dietz🇩🇪 · Hans-Werner Hammer🇩🇪 · Sebastian König🇩🇪 · Dam Thanh Son🇺🇸
The short-distance production of multi-particle states in high-energy nuclear reactions provides a unique way to study the low-energy properties of few-body systems. In particular, the production amplitude of multineutron systems is strongly constrained by an approximate conformal symmetry of the underlying theory. We calculate the full amplitude for the short-distance production of three particles with large scattering length in leading order pionless EFT, focusing on the cases of three neutrons and three spinless bosons. We investigate the signature of low-energy resonances and other correlations in the relative energy distributions. For the case of neutrons, we compare to the predictions from approximate conformal symmetry close to the unitary limit and calculate the range corrections up to next-to-next-to leading order.
Comments:
RevTeX 4.2, 13 pages, 11 figures,
Subjects:
Nuclear Theory (nucl-th); Quantum Gases (cond-mat.quant-gas)
arXiv:
2601.19408 [pdf]
PRC(2026)·1 citation
04
[Submitted on 27 Jan 2026]
Extracting Nucleon Resonance Transition GPDs from $e^{-} N \to e^{-} γ N π$ Deeply Virtual Compton Scattering
Matthew Rumley🇦🇺 · Anthony W. Thomas🇦🇺
We investigate the process in which Deeply Virtual Compton Scattering (DVCS) excites a baryon resonance. In particular, we assess, in DVCS leading to the Roper resonance, the relative importance of a "background'' process in which a pion is first emitted by the nucleon, which then undergoes a DVCS event. Our numerical results, using realistic DVCS kinematics, indicate that there can be measurable interference effects. They suggest that this process could substantially modify the experimentally observed cross sections at CLAS12-like kinematics, motivating their inclusion in precision analyses of DVCS experiments. We further find that in spite of this background, the transition to a Roper-like state through DVCS does contribute significantly to the $e^{-} N \to e^{-} γ N π$ cross section in some kinematic regions. This suggests that the creation of nucleon resonances via DVCS is a useful method for extracting information about the nucleon transition GPDs and the internal structure of the excited states.
Comments:
9 pages, 10 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2601.19434 [pdf]
PRD(2026)·1 citation
05
[Submitted on 27 Jan 2026]
The quasi-normal modes of relativistic Fokker-Planck kinetic theory
Lorenzo Gavassino🇬🇧
Employing the well-known unitary equivalence between Fokker-Planck operators and Schrödinger Hamiltonians, we compute the quasi-normal-mode spectrum of ultrarelativistic kinetic theories with momentum-space diffusion. We show that the collision operator reduces to a Dirac-delta Schrödinger problem in one spatial dimension, and to a Coulomb Schrödinger operator with hydrogenic spectrum in three dimensions. Finite spatial wavenumber appears as a perturbation of the associated quantum potential. The hydrodynamic mode is found to obey exact Fick-type diffusion at all real wavenumbers, whereas relativistic kinematics generically produces a continuous ballistic band in the non-hydrodynamic sector, a feature absent in the Newtonian regime.
Comments:
12 pages, 3 figures, publised in PRD (see https://journals.aps.org/prd/abstract/10.1103/6vfx-8kmm)
Subjects:
Nuclear Theory (nucl-th); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Theory (hep-th); Mathematical Physics (math-ph); math.MP (math.MP)
arXiv:
2601.19474 [pdf]
PRD(2026)·6 citations
06
[Submitted on 27 Jan 2026]
How transverse momentum conservation breaks azimuthal correlation factorization
Jia-Lin Pei🇨🇳 · Guo-Liang Ma🇨🇳 · Adam Bzdak🇵🇱
The breakdown of azimuthal two-particle correlation factorization, quantified by the ratios $r_{2}$ and $r_{3}$ , serves as a sensitive probe of transverse-momentum-dependent flow fluctuations. While hydrodynamic models predict $r_{3} \leq 1$ , experimental data from CMS in p-Pb collisions exhibit $r_{3} > 1$ , presenting a clear puzzle. We show that transverse momentum conservation (TMC) is the key mechanism dictating this factorization breakdown in small systems. We systematically calculate the effect of TMC as a function of the momentum difference between particles across various multiplicity and momentum ranges. Our results are in quantitative agreement with CMS p-Pb data for both $r_{2}$ and $r_{3}$ . A central finding is a sign rule: under TMC, the deviation $r_{n} - 1$ follows $(- 1)^{n + 1}$ , being negative for even and positive for odd harmonic orders $n$ . This work establishes an analytical framework to quantify transverse-momentum-dependent flow fluctuations and provides new insights into the origin of collectivity in small colliding systems.
Comments:
17 pages, 9 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2601.19475 [pdf]
0 citations
07
[Submitted on 27 Jan 2026]
Radial Oscillations and Stability of Neutron Stars with Antikaon Condensates
Manisha Kumari🇮🇳 · Sujan Kumar Roy🇮🇳 · Soumen Podder🇮🇳 · Suman Pal🇮🇳 · Gargi Chaudhuri🇮🇳
Radial oscillations provide a direct probe of the stability and compressibility of neutron stars and are highly sensitive to the equation of state of dense matter. In this work, we investigate the impact of antikaon condensates on the radial oscillation properties of neutron stars. We model neutron star matter using equations of state with a wide range of stiffness. For this purpose, both non-linear and density-dependent relativistic mean-field frameworks are employed to develop equations of state that are consistent with current astrophysical constraints. We further consider the emergence of antikaon condensates ( $K^{-}$ and $K ˉ^{0}$ ) in the stellar core, which modifies the pressure--energy density relation of dense matter. We find that the nature of the transition from nuclear matter to the condensed phase is sensitive to the antikaon optical potential depth and underlying equation of state. We compute the fundamental and higher-order radial oscillation modes for neutron stars containing antikaon condensates over a range of antikaon optical potential depths. Our results demonstrate that the antikaon optical potential depth plays a decisive role in governing the systematic shifts observed in the radial oscillation frequencies, while also significantly reducing the stability limits and maximum masses of neutron stars. These imprints of antikaon condensation on radial oscillation spectra provide a promising avenue for future multi-messenger observations and high-frequency gravitational-wave searches to directly probe and constrain the internal composition and equation of state of neutron stars.
Comments:
29 pages, 12 figures and 7 tables
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2601.19545 [pdf]
JCAP(2026)·0 citations
08
[Submitted on 27 Jan 2026]
Octet baryon electroweak form factors in dense nuclear matter
G. Ramalho🇰🇷 · K. Tsushima🇧🇷 · Myung-Ki Cheoun🇰🇷
Motivated by the necessity of developing theoretical models for studying the electroweak structure of baryons in a nuclear medium, we apply a covariant quark model to study interactions of baryons with nuclear matter. The electromagnetic and axial form factors of the octet baryons are determined by combining a covariant quark model that takes into account the meson cloud dressing of the baryon cores, developed for free space, with the quark-meson coupling model in the extension to the nuclear medium. We discuss the medium modifications on the electroweak form factors of octet baryons for the range of densities from $ρ = 0$ up to $ρ = 2 ρ_{0}$ , where $ρ_{0} = 0.15$ fm $^{- 3}$ is the normal nuclear matter density. We also study how the shape of the form factors is modified in finite nuclei due to the profile of the nuclear density distributions compared with calculations using the average density of the nucleus
Comments:
Contribution to proceedings of Baryons 2025. 5 pages, 2 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2601.19564 [pdf]
J.Subatomic Part.Cosmol.(2026)·0 citations
09
[Submitted on 27 Jan 2026]
A self-consistent calculation of non-spherical Bose-Einstein correlation functions with Coulomb final-state interaction
Márton I. Nagy🇭🇺 · Máté Csanád🇭🇺 · Dániel Kincses🇭🇺
Particle correlations and femtoscopy are a rich subfield of high-energy physics. As the experimental data become more precise, there is an increasing need for the theoretical calculations to provide better and more general descriptions of the measurements. One of the important new directions is the investigation of the precise shape of the Bose-Einstein correlation functions utilizing Lévy-stable distributions. This work is a direct follow-up to our previous study, in which we developed a novel method for calculating Bose-Einstein correlation functions including the Coulomb final-state interaction. In this paper, we present a self-consistent generalization of the previous approach to non-spherical source functions and investigate the validity of the previously applied approximations assuming spherical symmetry. We present a software package that includes the calculation of a fully three-dimensional correlation function including the Coulomb interaction.
Comments:
21 pages, 8 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th)
arXiv:
2601.19626 [pdf]
EPJC(2026)·1 citation
10
[Submitted on 27 Jan 2026]
Equation of State of Highly Asymmetric Neutron-Star Matter from Liquid Drop Model and Meson Polytropes
Elissaios Andronopoulos🇬🇷 · Konstantinos N. Gourgouliatos🇬🇷
We present a unified description of dense matter and neutron-star structure based on simple but physically motivated models. Starting from the thermodynamics of degenerate Fermi gases, we construct an equation of state for cold, catalyzed matter by combining relativistic fermion statistics with the liquid drop model of nuclear binding. The internal stratification of matter in the outer crust is described by $β$ -equilibrium, neutron drip and a gradual transition to supranuclear matter. Short-range repulsive interactions inspired by Quantum Hadrodynamics are incorporated at high densities in order to ensure stability and causality. The resulting equation of state is used as input to the Tolman--Oppenheimer--Volkoff equations, yielding self-consistent neutron-star models. We compute macroscopic stellar properties including the mass-radius relation, compactness and surface redshift that can be compared with recent observational data. Despite the simplicity of the underlying microphysics, the model produces neutron-star masses and radii compatible with current observational constraints from X-ray timing and gravitational-wave measurements. This work demonstrates that physically transparent models can already capture the essential features of neutron-star structure and provide valuable insight into the connection between dense-matter physics and astrophysical observables while they can also be used as easy to handle models to test the impact of more complicated phenomena and variations in neutron stars.
Comments:
This article belongs to the Special Issue Nuclear Symmetry Energy: From Finite Nuclei to Neutron Stars
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Theory (hep-th)
arXiv:
2601.19789 [pdf]
Symmetry(2026)·0 citations
11
[Submitted on 27 Jan 2026]
Unified Cranking-Model Description of Bohr and VMI Approache
Mohd Abu El Sheikh · Abdurahim A. Okhunov · Riad S. Masharfe · Anashon A. Yokubbayev
A unified analysis based on the cranking model is presented, demonstrating that both the Bohr and Variable Moment of Inertia (VMI) models arise as limiting cases of this framework. This result resolves the apparent contradiction between the two models by showing that they correspond to different physical limits of the same formalism. In addition, this analysis explicitly reveals the contribution of Coriolis effects to the rotational energy and moment of inertia.
Comments:
3 pages
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2601.19815 [pdf]
0 citations

Affiliations

first authorsco-authorsvia INSPIRE