Doubly-Charged Boson Production in $p \bar{p}$ Collisions at $\sqrt{s} =   1.96$ TeV
  It is suggested that the observed excess of muons in studies of $p \bar{p}$ collisions at $\sqrt{s} = 1.96$ TeV arises from the decay of doubly-charged bosons. Such particles are predicted in the 3-3-1 model where the electroweak gauge group is extended to $SU(3) \times U(1)$. 
Paul H. Frampton