WIMP annihilation and cooling of neutron stars

Abstract

We study the effect of WIMP annihilation on the temperature of a neutron star. We shall argue that the released energy due to WIMP annihilation inside the neutron stars might affect the temperature of stars older than 10 10 6 years, flattening out the temperature at 10 4 K for a typical neutron star.

Excluding Light Asymmetric Bosonic Dark Matter

“…In case of repulsive self-interactions, we exclude large range of WIMP masses and interaction cross sections which complements the constraints imposed by observations of the Bullet Cluster. Apart from direct searches, constraints on WIMPs can be set by observations of compact objects such as white dwarfs and neutron stars [4][5][6][7][8][9][10][11][12]. These constraints can be grouped in two types.…”

(Not)-constraining heavy asymmetric bosonic dark matter

“…In this case WIMPs carry a conserved quantum number and there is an asymmetry between the populations of WIMPs and anti-WIMPs, so that the annihilation is impossible in the present-day universe where only the WIMPs remain. Such kind of WIMPs can accumulate in a compact star quite efficiently as long as the WIMP-nucleon cross section exceeds a certain critical value which in the case of a neutron star is quite small (σ ∼ 10 −46 cm 2 ) [15], several orders of magnitude smaller than current limits from direct searches. Under certain circumstances, the amount of WIMPs accumulated during the lifetime of the star is sufficient to result in a gravitational collapse of the the WIMPs into a black hole.…”

“…Specifically, compact stars such as white dwarfs and neutron stars have been found to impose severe constraints on some dark matter models [14][15][16][17][18][19][20][21][22][23][24][25][26][27]. In principle, there are two types of effects that can take place in compact stars and can give rise to constraints on dark matter.…”

“…In principle, there are two types of effects that can take place in compact stars and can give rise to constraints on dark matter. The first type is related to the thermal evolution of compact stars [15,16,19,20]. In this case, annihilation of trapped weakly interacting massive particles (WIMPs) inside a compact star can produce significant amount of heat that can change the thermal evolution of the star at later times.…”

“…the temperature of the star as a function of the age) for typical neutron stars can be found, e.g. in [31] and [15]. Knowing the cooling curves, M sg (T ) and the WIMP accretion rate from Eq.…”