Work

Signatures of K − condensation on neutron star structure and f − mode frequencies

Year: 2025

Type: article

Abstract: Antikaon ( K − ) condensation within neutron star matter (NS) depends on the antikaon-nucleon interaction potential ( U K ). Its onset softens the equation of state (EOS), and the resulting changes in stellar structure may serve as indicators of the phase transition from nucleonic matter to K − condensed matter. We investigate the impact of K − condensation on NS properties using Bayesian inference with two RMF parameter sets: the stiff DD2 and the softer FSU EOS. Multimessenger observations from NICER and LIGO/Virgo constrain U K = − 104 . 72 − 12.48 + 13.82 MeV (DD2) and U K = − 66 . 46 − 3.42 + 2.47 MeV (FSU) respectively. Deeper K − potentials trigger condensation at a lower density, softening the EOS and lowering the corresponding maximum masses. While slopes of mass-radius and tidal deformability curves overlap between nucleonic and exotic EOSs, their curvature and f − mode oscillation properties (frequency and damping time) reveal features attributable to EOS softening. However, distinguishing the specific exotic degrees of freedom responsible for the softening remains an open challenge.

Source: Physics Letters B

DOI: 10.1016/j.physletb.2025.139990

Authors: Debanjan Guha Roy, Sarmistha Banik

Institution: Birla Institute of Technology and Science - Hyderabad Campus

Language: English

Topic: Pulsars and Gravitational Waves Research

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: diamond

Funder: Department of Science and Technology, Ministry of Science and Technology, India

Award: G5162876536