FCNC decays of SM fermions into a dark photon

Emidio Gabrielli, Barbara Mele, Martti Raidal +1

We analyze a new class of FCNC processes, the $f\to f^{\prime }\bar{\gamma }$ decays of a fermion $f$ into a lighter (same-charge) fermion $f^{\prime }$ plus a {\it massless} neutral ve…