Lepton polarization effects in Λb→Λℓ+ℓ- decay in family non-universal Z′ model

Possible manifestation of the family non-universal Z′ boson effects in lepton polarization in rare, exclusive baryonic Λb→Λℓ+ℓ- decay is examined. It is observed that the double lepton polarizations PNN, PTT and PTN are sensitive to the Z′ contribution. Moreover, it is found that the values of the polarized forward-backward asymmetry AFBLL are different in Standard Model (SM) and family non-universal Z′ model in different regions of q2, and therefore can serve as an efficient tool for establishing new physics beyond the SM.