Eur. Phys. J. C (2017) 77: 644
https://doi.org/10.1140/epjc/s10052-017-5206-x

Regular Article - Theoretical Physics

Leptogenesis and composite heavy neutrinos with gauge-mediated interactions

¹ AEC, Institute for Theoretical Physics, University of Bern, Sidlerstrasse 5, C3012, Bern, Switzerland
² Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, Via A. Pascoli, 06123, Perugia, Italy

^* e-mail: orlando.panella@pg.infn.it

Received: 5 July 2017
Accepted: 4 September 2017
Published online: 23 September 2017

Abstract

Leptogenesis is an appealing framework to account for the baryon asymmetry in the universe. To this end physics beyond the standard model is demanded. In this paper we investigate the possibility to attain successful leptogenesis with composite Majorana neutrinos. We work in the framework of effective gauge-mediated and contact interactions without any reference to an underlying compositeness theory. This approach is the one adopted in all current experimental searches for composite fermions at colliders. In the case of gauge-mediated interactions, we calculate the CP asymmetry in heavy composite neutrino decays. Both the direct and the indirect CP asymmetry are derived and resonant leptogenesis is also discussed. We find that the Sakharov conditions can be met and, for some choice of the parameters, the correct order of magnitude of the baryon asymmetry is reproduced.