Upper bound on tensor interaction in the decay π^-→e^-νγ

It is pointed out that a tensor four fermion interaction (u_Rσ_μνd_L) (e_rmRσ_μνν_L) produces through radiative corrections an interaction of the structure (u_Rd_L) (e_Rν_L, which is stronly limited by the decay π^-→e^-ν. The latter limit translates then into an upper bound of the strength of the tensor interaction which is at least two orders of magnitude lower than the value claimed by a recent measurement of the decay π^-→eνγ. Some aspects of a possible tensor interaction related to this bound are also discussed.