Speaker
Description
In recent times, several anomalies have been observed in the semileptonic decays of $B$ meson mediated by FCNC transitions $b \to s \mu^+ \mu^-$. These tantalizing signals point towards the possible existence of New Physics beyond the Standard Model. We explore $U(1)_{L_e-L_\mu}$ gauge extension of the Standard Model with particle content enlarged by three neutral fermions, of which the lightest one contributes to dark matter content of the Universe. The scalar sector is enriched with a $\tilde{R}_2$ scalar leptoquark doublet to investigate flavor anomalies in $B$-meson sector alongwith an additional scalar singlet to spontaneously break the new $U(1)$ symmetry. New physics contribution for $b \to s$ transition comes from penguin diagrams with $Z^\prime$, leptoquark and new fermions. We analyze the constraints on the model parameters from the established observables of $B \to K^{(*)} \mu^+ \mu^-$ and $B_s\to \phi \mu^+ \mu^-$ decay channels. We further discuss dark matter relic density and direct detection cross section in scalar and gauge portals. Utilizing the permissible parameter space consistent with both flavor and dark sectors, we illustrate the impact on various observables such as branching ratio, forward-backward asymmetry, longitudinal polarisation asymmetry, and also lepton non-universality of $\Lambda_b \to \Lambda ^* (1520) (\to pK) \ell ^+\ell ^-$ decay channel.
