Self-interacting dark matter with a vector mediator: kinetic mixing with U(1)$_{(B-L)_3}$ gauge boson

Understand

A spontaneously broken hidden U(1)$_h$ gauge symmetry can explain both the dark matter stability and the observed relic abundance.

• In this framework, the light gauge boson can mediate the strong dark matter self-interaction, which addresses astrophysical observations that are hard to explain in collisionless cold dark matter.
• Motivated by flavoured grand unified theories, we introduce right-handed neutrinos and a flavoured $B - L$ gauge symmetry for the third family U(1)$_{(B-L)_3}$.
• The unwanted relic of the U(1)$_h$ gauge boson decays into neutrinos via the kinetic mixing with the U(1)$_{(B - L)_3}$ gauge boson.