GeV scale dark matter and $B\to K+$ missing energy phenomenology in the $U(1{)}_{B-L}$ model

Abstract

We elucidate the recently observed discrepancy in the branching ratio of $B^{+}\to K^{+}$ +inv decay mode using a GeV scale scalar dark matter in an anomaly-free $U(1{)}_{B-L}$ gauge extension of the Standard Model. We constrain the new parameters by using consistency with the existing bounds on Dark matter relic density, direct detection, collider and BR($B\to K^{\ast }\nu \bar{\nu }$) measured at the Belle II experiment. We investigate couplings between the mediator and the SM fermions as well as the dark matter particle. We then estimate the branching ratios of $b\to s\nu \bar{\nu }$ decay processes such as $B\to (K^{+},K^{\ast })\nu \bar{\nu }$, $B_s\to (\eta ,{\eta }^{\prime })\nu \bar{\nu }$, $B_s\to \varphi \nu \bar{\nu }$ and $B_c\to (D_s,D_s^{\ast })\nu \bar{\nu }$ in a common parameter space, meeting the current experimental bounds of both sectors simultaneously.

Comments: 11 pages, 5 figures, Contribution to proceedings of the International Conference on Future Prospects in Neutrino and Astroparticle Physics (ICFPNAP 2024)