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 ΩDM 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 mnn2ññ for the right-handed sneutrinos, random matrices satisfying the ΩDM 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 mnn2ññ 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.