Leptogenesis and neutrino masses via pseudo-Dirac gauginos

In a U ( 1 ) R − L -symmetric supersymmetric model, pseudo-Dirac bino and wino can act like right-handed neutrinos, generating the light neutrino masses through a hybrid type I + III inverse seesaw mechanism. We investigate such a model to accommodate the baryon asymmetry of the universe together with neutrino masses. A pseudo-Dirac gaugino goes under particle-antiparticle oscillations. Possible C P violation in bino decays, induced by mixing with the neutrinos, can be enhanced in bino–antibino oscillations. Focusing on a long-lived bino, we show that its oscillations and decays can generate the observed baryon asymmetry while the wino is responsible for generating the neutrino masses. This mechanism requires a decoupled mass spectrum with a bino of mass M B ˜ ∼ O ( TeV ) and sfermions with mass M sf ≳ 50 TeV . Furthermore, for the bino to decay out-of-equilibrium before the electroweak sphalerons turn off, the messenger scale needs to be Λ M ∼ O ( 10 7 TeV ) . We discuss the displaced vertex signals at the LHC resulting from such a high messenger scale.