Limits on the non-standard interactions of neutrinos from e+e− colliders

We provide an effective Lagrangian analysis of contact non-standard interactions of neutrinos with electrons, which can be effectively mediated by extra particles, and examine the associated experimental limits. At present, such interactions are strongly constrained only for νμ: the bounds are loose for νe and absent for ντ. We emphasize the unique role played by the reaction e+e−→νν̄γ in providing direct constraints on such non-standard interactions.