Study of FCNC mediated Z boson effectin the semileptonic rare baryonic decays Λ < inf > b < /inf > → Λl < sup > + < /sup > l < sup > - < /sup >

Abstract

We study the effect of the FCNC mediated Z boson in the rare semileptonic baryonic decays Λ b → Λl + l -. We consider the model where the standard model fermion sector is extended by an extra vector-like down quark, as a consequence of which it allows for CP-violating Z mediated flavor changing neutral current at the tree level. We find that due to this non-universal Zbs coupling, the branching ratios of the rare semileptonic Λ b decays are enhanced reasonably from their corresponding standard model values and the zero point of the forward-backward asymmetry for Λ b → Λ μ+μ- is shifted to the left.