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arXiv · 1804.00067

Looking for the left sneutrino LSP with displaced-vertex searches

Inaki Lara·Daniel E. Lopez-Fogliani·Carlos Munoz·Natsumi Nagata·Hidetoshi Otono·Roberto Ruiz de Austri
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Abstract

We analyze a displaced dilepton signal expected at the LHC for a tau left sneutrino as the lightest supersymmetric particle with a mass in the range $45$-$100$ GeV. The sneutrinos are pair produced via a virtual $W$, $Z$ or $γ$ in the $s$ channel and, given the large value of the tau Yukawa coupling, their decays into two dileptons or a dilepton plus missing transverse energy from neutrinos can be significant. The discussion is carried out in the $μν$SSM, where the presence of $R$-parity violating couplings involving right-handed neutrinos solves the $μ$ problem and can reproduce the neutrino data. To probe the tau left sneutrinos we compare the predictions of the $μν$SSM with the ATLAS search for long-lived particles using displaced lepton pairs in $pp$ collisions at $\sqrt s= 8$ TeV, allowing us to constrain the parameter space of the model. We also consider an optimization of the trigger requirements used in existing displaced-vertex searches by means of a High Level Trigger that exploits tracker information. This optimization is generically useful for a light metastable particle decaying into soft charged leptons. The constraints on the sneutrino turn out to be more stringent. We finally discuss the prospects for the $13$ TeV LHC searches as well as further potential optimizations.

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Inaki Lara, Daniel E. Lopez-Fogliani, Carlos Munoz, Natsumi Nagata, Hidetoshi Otono, Roberto Ruiz de Austri. 2018-10-01. Looking for the left sneutrino LSP with displaced-vertex searches. https://doi.org/10.1103/physrevd.98.075004

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