FCNC and Rare B Decays in 3-3-1 Models
  An interesting extension of the Standard Model is based on the electroweak gauge group SU(3)_L x U(1). It requires three generations to cancel anomalies, treats the third generation differently than the first two, and has a rich phenomenology. There are several models, distinguished by the embedding of the charge operator into the SU(3)_L group and by the choice of fermion representations. In this Brief Report, we consider flavor-changing neutral currents in these models, concentrating on the P-Pbar mass difference, where P=(K, D, B, B_s), as well as B --> K l^+ l^-, B --> mu^+ mu^- and B_s --> mu^+ mu^- decays. Although the P-Pbar mass difference has been considered previously in some models, the rare B decays are new. We find that the strongest bounds come from the B-Bbar and Bs-Bs-bar mass differences. 
J.-Alexis Rodriguez (UNAL, Colombia) and Marc Sher (William and Mary)