title: Sterile neutrino dark matter and low scale leptogenesis from a charged scalar.
abstract: We show that novel paths to dark matter generation and baryogenesis are open when the standard model is extended with three sterile neutrinos [Formula: see text] and a charged scalar [Formula: see text]. Specifically, we propose a new production mechanism for the dark matter particle-a multi-keV sterile neutrino, [Formula: see text]-that does not depend on the active-sterile mixing angle and does not rely on a large primordial lepton asymmetry. Instead, [Formula: see text] is produced, via freeze-in, by the decays of [Formula: see text] while it is in equilibrium in the early Universe. In addition, we demonstrate that, thanks to the couplings between the heavier sterile neutrinos [Formula: see text] and [Formula: see text], baryogenesis via leptogenesis can be realized close to the electroweak scale. The lepton asymmetry is generated either by [Formula: see text]-decays for masses [Formula: see text] TeV, or by [Formula: see text]-oscillations for [Formula: see text] GeV. Experimental signatures of this scenario include an X-ray line from dark matter decays, and the direct production of [Formula: see text] at the LHC. This model thus describes a minimal, testable scenario for neutrino masses, the baryon asymmetry, and dark matter.
authors.affiliation: Laboratoire Charles Coulomb, UMR 5221 (CNRS/Université Montpellier 2), 34095  Montpellier, France.
authors.forename: Michele
authors.initials: M
authors.lastname: Frigerio
authors.affiliation: Institut für Theoretische Physik, Universität Münster, Wilhelm-Klemm-Straße 9, 48149  Münster, Germany.
authors.forename: Carlos E
authors.initials: CE
authors.lastname: Yaguna