Abstract
Within the framework of the mu nu mathrm{SSM}, a displaced dilepton signal is expected at the LHC from the decay of a tau left sneutrino as the lightest supersymmetric particle (LSP) with a mass in the range 45–100 GeV. We compare the predictions of this scenario with the ATLAS search for long-lived particles using displaced lepton pairs in pp collisions, considering an optimization of the trigger requirements by means of a high level trigger that exploits tracker information. The analysis is carried out in the general case of three families of right-handed neutrino superfields, where all the neutrinos get contributions to their masses at tree level. To analyze the parameter space, we sample the mu nu SSM for a tau left sneutrino LSP with proper decay length ctau > 0.1 , hbox {mm} using a likelihood data-driven method, and paying special attention to reproduce the current experimental data on neutrino and Higgs physics, as well as flavor observables. The sneutrino is special in the mu nu mathrm{SSM} since its couplings have to be chosen so that the neutrino oscillation data are reproduced. We find that important regions of the parameter space can be probed at the LHC run 3.
Highlights
By using the methods described in the previous sections, we evaluate the current and potential limits on the parameter space of our scenario from the displaced-vertex searches with the 8-TeV ATLAS result [30], and discuss the prospects for the 13-TeV searches
If we focus on the parameter points that can be probed at the 13-TeV LHC, the Scan 2 (S2) case predicts Rμ/e 3.6, and we can in principle distinguish this case from the Scans 1 (S1) case by measuring this ratio in the future LHC experiments such as the high-luminosity LHC
In the framework of the μνSSM, where there is R-parity violating (RPV) and the several decay branching ratios (BRs) of the lightest supersymmetric particle (LSP) significantly decrease the signals, there is a lack of experimental bounds on the masses of the sparticles
Summary
The μνSSM [9,37] is a natural extension of the MSSM where the μ problem is solved and, simultaneously, the neutrino data can be reproduced [9,13,14,37,38,39] This is obtained through the presence of trilinear terms in the superpotential involving right-handed neutrino superfields νic, which relate the origin of the μ-term to the origin of neutrino masses and mixing. With the low-energy bino and wino soft masses, M1 and M2, of the order of the TeV, and similar values for μ and mM as discussed above, this generalized seesaw produces three light neutral fermions dominated by the left-handed neutrino (νi ) flavor composition. A simplified formula for the effective mixing mass matrix of the light neutrinos is [38]:
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