Analysis of ${\Lambda}_b\rightarrow{\Lambda}l^+ l^-$ rare decays in a non-universal $Z'$ model

Abstract

We investigate the rare baryonic ${\Lambda}_b\rightarrow{\Lambda}l^+ l^-$ decays in a non-universal $Z'$ model, which is one of the well-motivated extensions of the standard model (SM). Considering the effects of $Z'$-mediated flavour-changing neutral currents (FCNCs) we analyse the differential decay rate, forward-backward asymmetries and lepton polarisation asymmetries for the ${\Lambda}_b\rightarrow{\Lambda}l^+ l^-$ decays. We find significant deviations from their SM predictions, which could indicate new physics arising from the $Z'$ gauge boson.