ar X iv : h ep - p h / 05 07 32 4 v 1 2 8 Ju l 2 00 5 Polarization effects in exclusive semileptonic Λ b → Λ l + l − decay

The independent helicity amplitudes in the Λb → Λl+l− decay in the standard model and its minimal extension, i.e., with the new vector type interactions, are calculated. We calculate various asymmetry parameters characterizing the angular dependence of the differential decay width for the cascade decay Λb → Λ(→ a + b)V ∗(→ l+l−) with polarized and unpolarized heavy baryons. The sensitivity of the asymmetry parameters to the new Wilson coefficients are analyzed. PACS numbers: 12.60.–i, 13.30.–a. 13.88.+e e-mail: [email protected] permanent address:Institute of Physics,Baku,Azerbaijan e-mail: [email protected]