We study lepton polarization asymmetries in the ${\Lambda }_b\to \Lambda l^{+}{l}^{-}$ decay using the most general model independent effective Hamiltonian. The dependence of the lepton polarizations and their combinations on the new Wilson coefficients are studied in detail. It is observed that there is a region for the new Wilson coefficients for which the branching ratio coincides with the standard model prediction, while lepton polarizations show considerable departure from the standard model.

• Received 5 March 2002

DOI:https://doi.org/10.1103/PhysRevD.65.115002