EFFECT OF BOTH Z AND Z′ MEDIATED FLAVOR-CHANGING NEUTRAL CURRENTS ON THE BARYONIC RARE DECAY Λb→Λℓ+ℓ-

Abstract

We study the effect of both Z and Z′ mediated flavor-changing neutral currents (FCNCs) on the Λb→Λℓ+ℓ-(ℓ = μ, τ) rare decay. We find the branching ratio is reasonably enhanced from its Standard Model value due to the effect of both Z and Z′ mediated FCNCs, and gives the possibility of new physics beyond the Standard Model. The contribution of Z′ boson depends upon the precise value of MZ′.