Dark Matter or Regular Matter in Neutron Stars? How to tell the difference from the coalescence of compact objects

The mirror Twin Higgs model is a candidate for strongly self-interacting dark matter. Since the model is a nearly identical copy of the Standard Model (SM), one expects that this model acquires interactions similar to the SM. Therefore, a neutron star entirely composed of mirror dark matter is possible. Our previous study showed mirror neutron stars are distinguishable from SM neutron stars. In this presentation, I will focus on two scenarios that produce a mirror matter admixed neutron star: mirror matter captured by a neutron star and the coalescence of a mirror neutron star and a SM neutron star. I will discuss the properties of the admixed star and the distinguishability from the observation perspective.