Resonant slepton production and right sneutrino dark matter in left-right supersymmetry

Abstract

Right-handed sneutrinos are natural components of left-right symmetric supersymmetric models where the gauge sector is extended to include right-handed weak interactions. Unlike in other models where right-handed sneutrinos are gauge singlets, here the right sneutrino is part of a doublet and could be a dark matter candidate whose annihilation proceeds via gauge interactions. We investigate this possibility, and find that relic density, low-energy observable and direct supersymmetry search constraints can be satisfied when the lightest supersymmetric particle is a right-handed sneutrino. We introduce benchmarks for left-right supersymmetric realizations where either a sneutrino or a neutralino is the lightest superpartner. We then study the LHC signals arising through resonant right-handed slepton production via a W R gauge-boson exchange that lead to final states enriched in leptons, additionally containing a large amount of missing transverse momentum, and featuring a low jet multiplicity. We find that such a resonant production would boost the chances of discovering these weakly interacting supersymmetric particles for a mass range extending beyond 1 TeV already with a luminosity of 100 fb −1 . Finally, we compare sneutrino versus neutralino scenarios, and comment on differences with other sneutrino dark matter models.

Charged Higgs Beyond the MSSM at the LHC

“…Because of the left-right symmetry, the righthanded fermions exist in SU(2) R doublets, making the right-handed neutrino a necessary ingredient in the model. In addition these models have several possible dark matter candidates, see [5], and may possibly solve both the strong and weak CP-problems.…”

“…Recently it was found that the gauge and Higgs sectors can also significantly contribute to the doubly charged Higgs mass, which opens up a window for lighter right sleptons and sneutrinos [22]. To obtain a heavy enough doubly charged Higgs boson, we set the λ R parameter to a large value, which leads to a large contribution to the doubly charged Higgs boson mass from the Higgs sector [5].…”

“…Close to the alignment limit, their dominant decay modes involve third generation fermions and the related LHC reach is thus similar as for the heavier states of the MSSM. We chose in [5] a moderate value for tan β so that the bounds stemming from both the direct heavy Higgs-boson searches in the H/A → ττ channel [24,25] are weaker and the contributions to the rare B s → µ µ decay are smaller than for large tan β . This has an additional advantage to suppress the mixing in the neutral Higgs sector, which may challenge the SM-nature of the lightest state and lead to a large deviation from the SM for the h → bb branching ratio [3].…”

“…In [5] we considered the following Higgs sector, with which seesaw type-II mechanism is possible and at the same time R-parity is conserved:…”

“…In order to evade all doubly charged Higgs LHC constraints, we fixed in [5] the model free parameters in a way in which the branching ratio of the doubly charged Higgs boson into muons and electrons stays below 10%.…”