Francois-Xavier Josse-Michaux

We study in detail the conditions to generate the baryon asymmetry of the universe from the annihilation of dark matter. This scenario requires a low energy mechanism for thermal baryogenesis, hence we first discuss some of these mechanisms together with the specific constraints due to the connection with the dark matter sector. Then we show that, contrary to what stated in previous studies, it is possible to generate the cosmological asymmetry without adding a light sterile dark sector, both in models with violation and with conservation of B−L. In addition, one of the models we propose yields some connection to neutrino masses.

We study in detail the conditions to generate the baryon asymmetry of the universe from the annihilation of dark matter. This scenario requires a low energy mechanism for thermal baryogenesis, hence we first discuss some of these mechanisms together with the specific constraints due to the connection with the dark matter sector. Then we show that, contrary to what stated in previous studies, it is possible to generate the cosmological asymmetry without adding a light sterile dark sector, both in models with violation and with conservation of B-L. In addition, one of the models we propose yields some connection to neutrino masses.

We present a U(1) extension of the standard model that accounts after breaking for the small neutrino masses and the observed dark matter abundance. From the presence of the dark matter candidate, an original scenario of leptogenesis emerges, viable in a restricted region of the parameter-space. Relying on a rich scalar sector, this model can deviate from standard model Higgs phenomenology.

We propose a UV completion of the inverse see-saw scenario using fermion SU(2) triplet representations. Within this framework, a variation of the standard thermal leptogenesis is achievable at the O(TeV) scale, owing to the presence of a viable dark matter candidate. This baryogenesis scenario is ruled out if a triplet fermion is observed at the LHC. The dark matter is given by the lightest neutral component of a complex scalar SU(2) triplet, with mass in the TeV range. The scalar sector, which is enriched in order to account for the small neutrino masses, is treated in detail and shows potentially sizable Higgs boson h \to \gamma \gamma\ rates together with large h invisible branching ratios.

A possible connection between the abundances of baryonic and dark matter (DM) has been explored so far mostly in the context of the so-called asymmetric DM. Recently, a very different mechanism, dubbed "WIMPy baryogenesis", has been proposed to relate the baryon asymmetry to DM annihilation. The DM candidate is a weakly interacting massive particle (WIMP), and the usual WIMP scenario is slightly extended to accommodate baryogenesis, which is accomplished around the time of DM freeze-out. We construct an effective field theory that encompasses a quite general class of models which implement the WIMPy baryogenesis. Under some reasonable, simplifying assumptions, we show that a good portion of the parameter space is allowed for these models, after experimental constraints are taken into account. Bounds from the LHC require that the WIMP be heavier than 400 GeV.

We study a seesaw-type extension of the Standard Model in which the symmetry group is enlarged by a global U(1). We introduce adequate scalar and fermion representations which naturally explain the smallness of neutrino masses. With the addition of a viable scalar Dark Matter candidate, an original scenario of leptogenesis emerges. We solve the relevant set of Boltzmann equations and show how leptogenesis can be successfully implemented at the TeV scale. The constraints on the scalar mass spectrum are derived and the Dark Matter phenomenology is discussed.

We study a seesaw-type extension of the standard model in which the symmetry group is enlarged by a global U(1). We introduce adequate scalar and fermion representations which naturally explain the smallness of neutrino masses. With the addition of a viable scalar dark matter candidate, an original scenario of leptogenesis emerges. We solve the relevant set of Boltzmann equations and show how leptogenesis can be successfully implemented at the TeV scale. The constraints on the scalar mass spectrum are derived and the dark matter phenomenology is discussed.