Neutrino mass, sneutrino dark matter and signals of lepton flavor violation in the MRSSM

We study the phenomenology of mixed-sneutrino dark matter in the Minimal R-symmetric Supersymmetric Standard Model (MRSSM). Mixed sneutrinos fit naturally within the MRSSM, as the smallness (or absence) of neutrino Yukawa couplings singles out sneutrino A-terms as the only ones not automatically forbidden by R-symmetry. We perform a study of randomly generated sneutrino mass matrices and find that (i) the measured value of Ω _dm is well within the range of typical values obtained for the relic abundance of the lightest sneutrino, (ii) with small lepton-number-violating mass terms m ² _nnññ for the right-handed sneutrinos, random matrices satisfying the Ω _dm constraint have a decent probability of satisfying direct detection constraints, and much of the remaining parameter space will be probed by upcoming experiments, (iii) the m ² _nnññ terms radiatively generate appropriately small Majorana neutrino masses, with neutrino oscillation data favoring a mostly sterile lightest sneutrino with a dominantly μ/τ-flavored active component, and (iv) a sneutrino LSP with a significant μ component can lead to striking signals of e-μ flavor violation in dilepton invariant-mass distributions at the LHC.