Possible electric charge nonconservation and dequantization in $SU(2)   \times U(1)$ models with hard symmetry breaking
  We study a novel type of extensions of the Standard Model which include a hard mass term for the U(1) gauge field and, optionally, the additional scalar multiplets spontaneously violating the electric charge conservation. Contrary to the case of abelian massive electrodynamics, in these theories the massiveness of photon necessarily implies non-conservation (and also dequantization) of the electric charge (even in the absence of spontaneous breakdown of the electromagnetic symmetry). On the other hand, unexpectedly, there exist models with charge non-conservation where it is possible to keep the photon mass zero (at least, at the tree level). 
A.Yu.Ignatiev and G.C.Joshi