Nuclear Theory·nucl-th

Wednesday·November 5, 2025

6 papers—3 primary·3 cross-listed

01
[Submitted on 4 Nov 2025]
General relativistic study of $f$ -mode oscillations in neutron stars with gravitationally bound dark matter
Pinku Routaray🇮🇳
A comprehensive investigation of nonradial oscillations in neutron star (NS) admixed with gravitationally bounded dark matter (DM) is carried out within the framework of full general relativity. The relativistic mean field (RMF) formalism is employed to illustrate the hadronic equation of state (EOS), while a physically motivated, gravitationally captured, non-uniform fermionic Higgs-portal DM component is incorporated to model DM-admixed NS. The DM distribution is characterized by two free parameters: $α M_{χ}$ , an effective control parameter that combines the DM concentration and the DM candidate mass, and $β$ , a steepness parameter controlling the DM density distribution. The quasi normal mode (QNM) characteristics such as fundamental ( $f$ ) mode frequency and its corresponding gravitational-wave (GW) damping time ( $τ$ ) is calculated for DM-admixed NS by solving the general relativistic perturbed equations involving axial as well as polar modes. The study demonstrates how the inclusion of DM distribution modifies the $f$ -mode frequency and enhances the damping rate, reflecting a stronger coupling between matter and spacetime perturbations. Considering DM effects, the correlation analysis among DM model parameters, NS observables and QNM characteristics also carried out. Analytic fits for the $f - C - τ$ and $f - Λ - τ$ relations are constructed and calibrated for DM-admixed NS models. Building upon asteroseismic universal relations (URs), multimessenger constraint from the GW170817 event is employed by mapping the tidal deformability $Λ_{1.4}$ into the $(f_{1.4}, τ_{1.4})$ space, thereby providing observational bounds on the oscillation properties of canonical DM-admixed NS model.
Comments:
Published (Physics of the Dark Universe 53 (2026) 102369)
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
arXiv:
2511.02443 [pdf]
Phys.Dark Univ.(2026)·3 citations
02
[Submitted on 4 Nov 2025]
Revisiting the three-kaon interaction and its relation with $K (1460)$
Michael Döring🇺🇸 · Kanchan P. Khemchandani🇧🇷 · Alberto Martínez Torres🇧🇷
We test the hypothesis of $K (1460)$ being a hadronic $J^{P} = 0^{-}$ molecule through nonperturbative $S$ -wave $K K K ˉ$ , $K π π$ , $K π η$ coupled-channel dynamics in a three-body unitary isobar approach. The scalar two-body coupled-channel resonances $f_{0} (500)$ , $f_{0} (980)$ , $a_{0} (980)$ and $K_{0}^{*} (700)$ are generated in the subsytems in amplitudes that match phase shifts from experiment. In a first step, previous results in the limit of mass-degenerate, stable $f_{0}$ and $a_{0}$ isobars are reproduced. Once the full seven-coupled channel model is switched on, other $S$ -matrix effects obscure and modify the resonance signal, including complex thresholds, a two-body cusp, and a triangle singularity at threshold.
Comments:
29 pages, 14 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2511.02543 [pdf]
PRD(2026)·5 citations
03
[Submitted on 4 Nov 2025]
A Bayesian Inference of Hybrid Stars with Large Quark Cores
Milena Albino🇵🇹 · Tuhin Malik🇵🇹 · Márcio Ferreira🇵🇹 · Constança Providência🇵🇹
Neutron stars (NSs) are interesting objects capable of reaching densities unattainable on Earth. The properties of matter under these conditions remain a mystery. Exotic matter, including quark matter, may be present in the NS core. In this work, we explore the possible compositions of NS cores, in particular, the possible existence of large quark cores. We use the Relativistic Mean Field (RMF) model with nonlinear terms for the hadron phase and the Nambu-Jona-Lasinio (NJL) model and Mean Field Theory of Quantum Chromodynamics (MFTQCD) for the quark phase. Through Bayesian inference, we obtain different sets of equations: four sets with hybrid equations and one set with only the hadron phase. We impose constraints regarding the properties of nuclear matter, X-ray observational data from NICER, gravitational wave data from the binary neutron star merger GW170817, perturbative QCD (pQCD) calculations, and causality. The MFTQCD allows for a phase transition to quark matter at low densities, just above saturation density, while for the NJL sets, the phase transition occurs above twice the saturation density. As a result, the MFTQCD model predicts the presence of quark matter in the inner core of 1.4 M $_{⊙}$ NSs, while NJL models suggest a low probability of quark matter in the interior of a 1.4 M $_{⊙}$ NS. Both models predict the existence of quark matter in 2 M $_{⊙}$ NSs. The slope of the mass-radius curve has been shown to carry information about the presence of quark matter. In particular, a positive slope at 1.8 M $_{⊙}$ indicates the presence of non-nucleonic matter. A hybrid star with a stiff quark equation of state could explain a larger radius in more massive stars, such as two solar mass stars, compared to canonical NSs.
Comments:
24 pages, 17 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2511.02653 [pdf]
PRD(2026)·13 citations

Affiliations

first authorsco-authorsvia INSPIRE

General relativistic study of f-mode oscillations in neutron stars with gravitationally bound dark matter

Revisiting the three-kaon interaction and its relation with K(1460)

A Bayesian Inference of Hybrid Stars with Large Quark Cores

Affiliations

General relativistic study of $f$ -mode oscillations in neutron stars with gravitationally bound dark matter

Revisiting the three-kaon interaction and its relation with $K (1460)$