Testing the nature of neutrinos from four-body τ decays

Abstract

This paper discusses four-body lepton number violating tau decay. We study the processes and to determine the nature of the neutrino. The first process violates the lepton number by two units, which can only happen through an internal Majorana. The second one conserves the lepton number but violates the lepton flavor, which can take place with both a Majorana neutrino and a Dirac neutrino. We calculate their branching ratio (BR) and differential BR to distinguish between the Majorana neutrino and the Dirac neutrino. We also propose an experiment to perform this detection.