Eur. Phys. J. C (2006) 45: 151-158
https://doi.org/10.1140/epjc/s2005-02407-6

Theoretical Physics

Study of FCNC mediated Z boson effectin the semileptonic rare baryonic decays Λ _b → Λl ⁺ l ^-

¹ Department of Physics, National Tsing Hua University, Hsinchu, Taiwan 300
² University of Hyderabad, School of Physics, 500 046, Hyderabad, India

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.