Speaker
Description
We explore lepton flavor violating (LFV) dark matter (DM) interactions within an effective field theory framework, considering the operators of the form $\bar \ell_j \Gamma \ell_i,{\tt DM}^2$ for $(ij) = (\mu e,, \tau e,, \tau \mu)$ and where DM can be scalar, fermion, and vector. We analyze the three-body decay $\ell_i \to \ell_j + {\tt DM} + {\tt DM}$, showing its utility in probing operator structure and DM mass. Using current bounds on LFV decays with invisible final states, we set strong constraints on the effective scale. For the $\mu e$ case, we also study the radiative decay $\mu \to e + {\tt DM} + {\tt DM} + \gamma$, and examine muonium invisible decays, which can be significantly enhanced. A future observation of para-muonium invisible decay would provide a clear signal of such LFV DM interactions.
