Impact of vector leptoquark on $\bar B \to \bar K^* l^+ l^-$ anomalies

Abstract

Motivated by the recent measurement of the lepton flavour nonuniversality ratio $R_{K^*}$ by the LHCb Collaboration, we study the implications of vector leptoquarks on the observed anomalies associated with the $\bar B \to \bar K^* l^+ l^-$ decay processes. The leptoquark couplings are constrained from the measured branching ratios of $B_s \to l^+ l^-$, $K_L \to l^+ l^-$ and $B_s \to \mu^\mp e^\pm$ processes. Using these constrained couplings, we estimate the branching ratios, forward-backward and lepton polarization asymmetries and also the form factor independent optimized observables ($P_{i}^{(\prime)}$) for $\bar B \to \bar K^* l^+ l^-$ modes in the high recoil limit. We also study the other lepton flavour universality violating observables, such as $Q_{F_{L, T}}$, $Q_{i}$ and $B_{5, 6s}$, where $i=1,2,\cdots6, 8$. Furthermore, we investigate the lepton flavour violating $K_L \to \mu^\mp e^\pm$ decay process in this model.