On the 1 m² corrections to the form-factors in Λ_b→Λ_ceν_e decays

Model-independent bounds are presented for the form-factors describing the semileptonic decay Λ_b→Λ_ceν_e at the end-point of the lepton energy spectrum. For the axial-vector form-factor f{hook}₁^A(1) we obtain f{hook}₁^A(1)≤0.960/0.935, where the uncertainty arises from the value of μ_π², the average kinetic energy of the b quark inside the Λ_b baryon. A bound is given on the forward matrix element of the axial current in a Λ_b baryon which is relevant for the inclusive semileptonic decays of the polarized Λ_b decays.