Constraints on fourth generation Majorana neutrinos

Abstract

We investigate the possibility of a fourth sequential generation in the lepton sector. Assuming neutrinos to be Majorana particles and starting from a recent - albeit weak - evidence for a non-zero admixture of a fourth generation neutrino from fits to weak lepton and meson decays we discuss constraints from neutrinoless double beta decay, radiative lepton decay and like-sign di-lepton production at hadron colliders.

Comments: 6 pages, Proceedings of the 16th International Symposium on Particles, Strings and Cosmology (PASCOS2010), Valencia (Spain), July 19th - 23rd, 2010