Dark matter and bubble nucleation in old neutron stars

A Herrero,M A Pérez-García,C Albertus,J Silk

doi:10.1103/physrevd.100.103019

Abstract

We study the probability for nucleation of quark matter droplets in the dense cold cores of old neutron stars induced by the presence of a self-annihilating dark matter component, $\chi$. Using a parameterized form of the equation of state for hadronic and quark phases of ordinary matter, we explore the thermodynamic conditions under which droplet formation is facilitated by the energy injection from $\chi$ self-annihilations. We obtain the droplet nucleation time as a function of the dark matter candidate mass, $m_\chi$. We discuss further observational consequences.

Highlights

Neutron stars (NSs) are compact astrophysical stellar objects where the low temperature and high density regions of ordinary matter phase space can be explored [1]
We study the probability for nucleation of quark matter droplets in the dense cold cores of old neutron stars induced by the presence of a self-annihilating dark matter component, χ
Using a parametrized form of the equation of state for hadronic and quark phases of ordinary matter, we explore the thermodynamical conditions under which droplet formation is facilitated by the energy injection from χ self-annihilations

Summary

Introduction

Neutron stars (NSs) are compact astrophysical stellar objects where the low temperature and high density regions of ordinary matter phase space can be explored [1] Their measured masses do not exceed a maximum value MÃ ∼ 2 M⊙ and radii RÃ ∼ 11–13 km. Central nucleon number densities are thought to be several times that of nuclear saturation density, n0 ∼ 0.17 fm−3 and effective measured temperatures are in the range T∞ ∼ 105.3–106 K for old NSs with lifetimes τNS ≳ 104 yr [3] Under these conditions ordinary matter is typically degenerate since baryonic Fermi energies are of the order of EF;B ∼ 30 MeV, whereas the internal temperature drops below T ∼ 1 MeV ðkB 1⁄4 1Þ within ∼100 seconds after the birth of the NS [4].

Objectives

Results

Conclusion