Efficiency and maximal CP-asymmetry of scalar triplet leptogenesis
Abstract
We study thermal leptogenesis induced by decays of a scalar SU(2)_L triplet. Despite the presence of gauge interactions, unexpected features of the Boltzmann equations make the efficiency close to maximal in most of the parameter space. We derive the maximal CP asymmetry in triplet decays, assuming that it is generated by heavier sources of neutrino masses: in this case successful leptogenesis needs a triplet heavier than 2.8 10^{10} GeV and does not further restrict its couplings, allowing detectable mu --> e gamma, tau --> mu gamma rates in the context of supersymmetric models. Triplet masses down to the TeV scale are viable in presence of extra sources of CP-violation.
Cite
@article{arxiv.hep-ph/0510008,
title = {Efficiency and maximal CP-asymmetry of scalar triplet leptogenesis},
author = {Thomas Hambye and Martti Raidal and Alessandro Strumia},
journal= {arXiv preprint arXiv:hep-ph/0510008},
year = {2009}
}
Comments
12 pages, 6 figures. Interference term added to eq. (16d), figures recomputed (the difference is almost invisible)