Search for imprints of isovector–scalar mesons and kaon condensation in binary neutron star inspiral gravitational waves

Abstract Gravitational wave signals emitted during the binary neutron star inspiral phase offer a promising avenue for probing stellar internal composition. Isovector–scalar mesons and kaon condensation are thought to play pivotal roles in characterizing asymmetric nuclear matter and constraining the dense nuclear equation of state. This study explores whether their potential effects in neutron stars can be identified from inspiral gravitational wave frequencies, retarded times and orbital phases. Our analysis reveals the isovector–scalar meson accelerates the inspiral process, leading to shorter retarded times and lower maximum gravitational wave frequencies compared to standard binary neutron star systems, while binary systems influenced by kaon condensation exhibit even shorter inspiral retarded times and lower gravitational wave frequencies than those influenced solely by isovector–scalar mesons. Quantitatively, the incorporation of kaon condensation leads to a reduction of approximately 200 Hz in the maximum inspiral gravitational wave frequency, and the variations in retarded times across different kaon potentials reach approximately five milliseconds, whereas the corresponding variations induced by isovector–scalar mesons are around one millisecond. Combined with observable mass–radius relationships and tidal deformabilities, our findings strongly suggest that inspiral gravitational wave signals could serve as a strategic probe for identifying potential isovector–scalar and kaon mesons.