B anomalies and dark matter: a complex connection

Understand

We study an extension of the Standard Model that addresses the hints of lepton flavour universality violation observed in $B\to K^{(*)} l^+l^-$ decays at LHCb, while providing a viable candidate for dark matter.

• The model incorporates two new scalar fields and a Majorana fermion that induce one-loop contributions to $B$ meson decays.
• We show that agreement with observational data requires the new couplings to be complex and that the Majorana fermion can reproduce the observed dark matter relic density.
• This combination of cosmological and flavour constraints sets an upper limit on the dark matter and mediator masses.