Quasi-Dirac neutrinos at the LHC
- 68 Downloads
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, R ll , is equal to R ll = 1 (R ll = 0) for Majorana (Dirac) neutrinos. We clarify under which conditions the ratio R ll can assume values different from 0 and 1, and we argue that the precise value 0 < R ll < 1 is controlled by the mass splitting versus the width of the quasi-Dirac resonances. A measurement of R ll = 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 R ll 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 W R exchange.
KeywordsBeyond Standard Model Neutrino Physics
This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited.
- J.C. Pati and A. Salam, Lepton number as the fourth color, Phys. Rev. D 10 (1974) 275 [Erratum ibid. D 11 (1975) 703] [INSPIRE].
- CMS collaboration, Search for a heavy neutrino and right-handed W of the left-right symmetric model in pp collisions at 8 TeV, CMS-PAS-EXO-12-017, CERN, Geneva Switzerland (2012).