Searching for left sneutrino LSP at the LHC

Abstract

We analyze relevant signals expected at the LHC for a left sneutrino as the lightest supersymmetric particle (LSP). The discussion is carried out in the "μ from V" supersymmetric standard model (μνSSM), where the presence of R-parity breaking couplings involving right-handed neutrinos solves the μ problem and reproduces neutrino data. The sneutrinos are pair produced via a virtual W, Z or γ in the s channel. From the prompt decay of a pair of left sneutrinos LSPs of any family, a significant diphoton signal plus missing transverse energy (MET) from neutrinos can be present in the mass range 118-132 GeV, with 13 TeV center-of-mass energy and an integrated luminosity of 100 fb-1. In addition, in the case of a pair of tau left sneutrinos LSPs, given the large value of the tau Yukawa coupling diphoton plus leptons and/or multileptons can appear. We find that the number of expected events for the multilepton signal, together with properly adopted search strategies, is sufficient to give a significant evidence for a sneutrino of mass in the range 130-310 GeV, even with the integrated luminosity of 20 fb-1. In the case of the signal producing diphoton plus leptons, an integrated luminosity of 100 fb-1 is needed to give a significant evidence in the mass range 95-145 GeV. Finally, we discuss briefly the presence of displaced vertices and the associated range of masses.