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 “[Formula: see text] from [Formula: see text]” supersymmetric standard model [Formula: see text], where the presence of [Formula: see text]-parity breaking couplings involving right-handed neutrinos solves the [Formula: see text] problem and reproduces neutrino data. The sneutrinos are pair produced via a virtual [Formula: see text], [Formula: see text] or [Formula: see text] in the [Formula: see text] 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[Formula: see text]. 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[Formula: see text]. In the case of the signal producing diphoton plus leptons, an integrated luminosity of 100 fb[Formula: see text] 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.