Right sneutrino with Δ⁢𝐿���=2 masses as nonthermal dark matter

Abstract

We consider the minimal supersymmetric standard model (MSSM) with right-chiral neutrino superfields with Majorana masses, where the lightest right-handed sneutrino dominated scalars constitutes nonthermal dark matter (DM). The Δ⁢𝐿=2 masses are subject to severe constraints coming from freeze-in relic density of such DM candidates as well as from sterile neutrino freeze-in. In addition, big bang nucleosynthesis and freeze-out of the next-to-lightest superparticle shrink the viable parameter space of such a scenario. We examine various Δ⁢𝐿=2 mass terms for families other than that corresponding to the LSP sneutrino. Δ⁢𝐿=2 masses are difficult to reconcile with a right-sneutrino DM, unless there is either (a) a hierarchy of about 3 orders of magnitudes among various supersymmetry-breaking mass parameters, or, (b) strong cancellation between the Higgsino mass and the trilinear supersymmetry breaking mass parameter for sneutrinos.