Sterile neutrino dark matter and low scale leptogenesis from a charged scalar

Michele Frigerio; Carlos E. Yaguna

doi:10.1140/epjc/s10052-014-3252-1

EPJ

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2023 Impact factor 4.2

Particles and Fields

Open Access

Eur. Phys. J. C (2015) 75: 31
https://doi.org/10.1140/epjc/s10052-014-3252-1

Regular Article - Theoretical Physics

Sterile neutrino dark matter and low scale leptogenesis from a charged scalar

Michele Frigerio¹ and Carlos E. Yaguna²^*

¹ Laboratoire Charles Coulomb, UMR 5221 (CNRS/Université Montpellier 2), 34095 , Montpellier, France
² Institut für Theoretische Physik, Universität Münster, Wilhelm-Klemm-Straße 9, 48149 , Münster, Germany

^* e-mail: carlos.yaguna@uni-muenster.de

Received: 24 September 2014
Accepted: 26 December 2014
Published online: 27 January 2015

Abstract

We show that novel paths to dark matter generation and baryogenesis are open when the standard model is extended with three sterile neutrinos $$N_i$$ and a charged scalar $\delta ^+$ . Specifically, we propose a new production mechanism for the dark matter particle—a multi-keV sterile neutrino, $$N_1$$ —that does not depend on the active-sterile mixing angle and does not rely on a large primordial lepton asymmetry. Instead, $$N_1$$ is produced, via freeze-in, by the decays of $\delta ^+$ while it is in equilibrium in the early Universe. In addition, we demonstrate that, thanks to the couplings between the heavier sterile neutrinos $N_{2,3}$ and $\delta ^+$ , baryogenesis via leptogenesis can be realized close to the electroweak scale. The lepton asymmetry is generated either by $N_{2,3}$ -decays for masses $M_{2,3}\gtrsim$ TeV, or by $N_{2,3}$ -oscillations for $M_{2,3}\sim$ GeV. Experimental signatures of this scenario include an X-ray line from dark matter decays, and the direct production of $\delta ^+$ at the LHC. This model thus describes a minimal, testable scenario for neutrino masses, the baryon asymmetry, and dark matter.