New neutrino interactions at large colliders

35th International Conference of High Energy Physics - ICHEP2010, July 22-28, 2010, Paris (France). PoS(ICHEP 2010) 296.We update present bounds on the helicity of the neutrinos produced in muon decay, including e+e− ! f f LEP 2 data. These significantly reduce the limits derived from all the other electroweak precision data. In Standard Model extensions designed to maximize the RH neutrino production in such a decay the neutrino deficit eventually observable in a near detector at a neutrino factory can be of the order of 5 %. Motivated by the current LHC run at 7 TeV, we also update previous work providing discovery limits on see-saw mediators at this centre of mass energy. Lepton triplets with 200 GeV could be discovered with luminosities of 1 - 1.5 fb−1. Scalar triplets of the same mass might be seen with 0.75 - 3 fb−1. What makes their search also attractive in the first LHC analyses.This work has been partially supported by MICINN (FPA2006-05294), Junta de Andalucía (FQM 101, FQM 03048) and the European Union (MRTN-CT-2006-035505)