General Conditions for Lepton Flavour Violation at Tree- and 1-Loop Level

Understand

In this work, we compile the necessary and sufficient conditions a theory has to fulfill in order to ensure general lepton flavour conservation, in the spirit of the Glashow-Weinberg criteria for the absence of flavour-changing neutral currents.

• At tree-level, interactions involving electrically neutral and doubly charged bosons are investigated.
• We also investigate flavour changes at 1-loop level.
• In all cases we find that the essential theoretical requirements can be reduced to a few basic conditions on the particle content and the coupling matrices.