Abstract: We implement the asymmetric dark matter framework, linking the ordinary and dark matter abundances, within a supersymmetric context. We consider a supersymmetric model that respects an approximate U(1)R symmetry, which is broken in such a way that at high temperature the R breaking sector mediate processes in equilibrium, but at the SUSY mass scale, the sparticles asymmetry is frozen. In this framework, the gravitino serves as the dark matter candidate, and its mass is predicted to be similar to 10 GeV to match the observed relic abundance. We identify several realistic spectra; however, the requirement for the Next-to-Lightest Supersymmetric Particle (NLSP) to decay into the gravitino before Big Bang Nucleosynthesis constrains the viable spectrum to masses above 2 TeV.

Abstract: We study the implications for leptogenesis in a class of left-right symmetric model, where all fermion masses are induced through the Universal Seesaw mechanism. Unlike conventional analyses, we do not use the decays of the neutrino embedded in the right-chiral lepton doublet, but rather those of the gauge-singlet mediators required for neutrino mass generation in the canonical Type-I seesaw. This model features a generalized parity symmetry, which is motivated by the solution to the strong CP problem. Since this discrete symmetry doubles the fermionic degrees of freedom in this model, we can generate the required CP violation in the heavy fermion decays with only a single generation of mediators. One of the distinct features of our scenario is that the bounds from thermalization or washout via gauge interactions typically encountered in the canonical left-right symmetric models do not apply here. Moreover, the heavy mediators can decay to both the left and the right-chiral neutrinos, leading to a cancellation in the resulting baryon asymmetry for decays above the left-right symmetry breaking scale. We discuss ways to avoid this cancellation and show that low scale left-right symmetry breaking above the current collider limits v(R )> 18 TeV is viable. The right chiral neutrinos also obtain their masses from the seesaw mechanism, and the lightest one turns out to have a sub-eV scale mass. We find that its abundance is consistent with standard cosmology, and it acts as potentially observable dark radiation.

Abstract: We discuss spontaneous Leptogenesis in the Type II Seesaw model of neutrino masses featuring an electroweak triplet scalar T in a coherent pseudo Nambu-Goldstone boson (pNGB) background. In the “wash-in” scenario the inverse decays of Higgs bosons to T generate a chemical potential for the triplet, that is then transmitted to the lepton sector via the leptonic decays of T. Our mechanism works with a single triplet, that can be as light as 1 TeV, and has a vacuum expectation value VT in the window O (1 keV) < vT < O (1 MeV). This range of VT can lead to appreciable decays of the triplet's doubly charged component into both same sign di-leptons and same sign pairs of W-bosons, which could potentially allow for an experimental distinction from a recently proposed inflationary Type II Seesaw Affleck-Dine scenario preferring the leptonic mode. In the “singlet-doublet-triplet Majoron” UV-completion of the Type II Seesaw model, the required pNGB is automatically included in the form of the Majoron, that originates from the phase of the lepton number breaking singlet scalar. The coherent motion of the Majoron can furthermore explain the dark matter relic abundance via the kinetic misalignment mechanism. Cogenesis of dark matter and the baryon asymmetry can work for a lepton number breaking scale of O(10(5) GeV) < v(sigma) < O(10(8) GeV) and a Majoron mass of O(1 eV) > m(j )> O (1 & micro;eV).