Within an effective field theory framework, we discuss the possibility to discriminate among different operators that contribute to lepton flavor violating (LFV) $\tau$ decays. Correlations among decay rates in different channels are shown to provide a basic handle to unravel the origin of LFV in these processes. More information about the underlying dynamics responsible for LFV can be gathered from differential distributions in three-body decays like $\tau \to \mu \pi \pi$ or $\tau \to 3\mu$: these are considered in some detail. We incorporate in our analysis recent developments in the determination of the hadronic form factors for $\tau \to \mu \pi \pi$. Future prospects for the observation of LFV $\tau$ decays and its interpretation are also discussed.

• Received 28 March 2014

DOI:https://doi.org/10.1103/PhysRevD.89.095014