Fourth Generation Lepton Sectors with Stable Majorana Neutrinos: From LEP to LHC

Understand

I analyze a fourth generation lepton sector in which the lightest particle is a stable Majorana neutrino.

• In this scenario fourth generation neutrinos have both a Dirac and Majorana mass, resulting in two Majorana neutrino mass eigenstates.
• A reanalysis of LEP's lower mass bound is performed on stable Majorana neutrinos from the Z width and the lower mass bound is loosened.
• I also extrapolate LEP's SUSY squark search with a 2 jet plus missing missing energy final state to the production and decay of a pair of heavy Majorana neutrinos; here it is expected that significant regions of the neutrino mass plane may be ruled out.