Enhanced neutrino emissivities in pseudoscalar-mediated Dark Matter annihilation in Neutron Stars

Understand

We calculate neutrino emissivities from self-annihilating dark matter ($\chi$) in the dense and hot stellar interior of a (proto)neutron star.

• Using a model where dark matter interacts with nucleons in the stellar core through a pseudoscalar boson ($a$) we find that the neutrino production rates from the dominant reaction channels $\chi \chi \rightarrow \nu \bar{\nu}$ or $\chi \chi \rightarrow a a$, with subsequent decay of the mediator $ a \rightarrow \nu \bar{\nu}$, could locally match and even surpass those of the standard neutrinos from the modified nuclear URCA processes at early ages.
• We find that the emitting region can be localized in a tiny fraction of the star (less than a few percent of the core volume) and the process can last its entire lifetime for some cases under study.
• We discuss the possible consequences of our results for stellar cooling in light of existing dark matter constraints.