2016/07/31 by G. Anamiati, M. Hirsch, E. Nardi · 2 citations
Physics and Astronomy · #hep-ph
paper · pdf · doi:10.1007/jhep10(2016)010
arxiv created 2016/10/28 · arxiv updated 2016/11/03
Lepton number violation is searched for at the LHC using same-sign leptons plus jets. The standard lore is that the ratio of same-sign lepton to opposite-sign lepton events, Rll, is equal to Rll=1 (Rll=0) for Majorana (Dirac) neutrinos. We argue that for "quasi-Dirac" neutrinos, Rll can have any value between 0 and 1, the precise value being controlled by the mass splitting versus the width of the quasi-Dirac resonances. A measurement of Rll≠ 0,1 would then contain valuable information about the origin of neutrino masses. We consider as an example the inverse seesaw mechanism in a left-right symmetric scenario, which is phenomenologically particularly interesting since all the heavy states in the high energy completion of the model could be within experimental reach. A prediction of this scenario is a correlation between the values of Rll and the ratio between the rates for heavy neutrino decays into standard model gauge bosons, and into three body final states ljj mediated by off-shell WR exchange.