New neutrino interactions at large colliders

TL;DR

This paper updates bounds on neutrino helicity from collider data, explores potential signals of right-handed neutrinos and see-saw mediators at the LHC, and discusses their discovery prospects.

Contribution

It provides new constraints on neutrino helicity and evaluates the discovery potential of see-saw mediators and lepton triplets at the 7 TeV LHC.

Findings

Neutrino helicity bounds are significantly tightened by LEP 2 data.

Lepton triplets of 200 GeV could be discovered with 1-1.5 fb^-1.

Scalar triplets of similar mass might be detected with 0.75-3 fb^-1.

Abstract

We update present bounds on the helicity of the neutrinos produced in muon decay, including e+ e- -> fbar 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.