Flavor Changing Neutral Current Effects and CP Violation in the Minimal 3-3-1 Model

Abstract

We investigate in detail the flavor structure of the minimal 331 model and its implications for several flavor changing neutral current (FCNC) processes. In this model, where the weak SU(2)_L gauge group of the Standard Model is extended to a SU(3)_L, the by far dominant new contributions come from an additional neutral Z' gauge boson, that can transmit FCNCs at tree-level. At the same time, electroweak precision observables receive new contributions only at the loop level and do not constrain the model very strongly. In our analysis, we take into account new CP violating effects that have been neglected in earlier analyses, and account for a general flavor structure without reference to a certain parameterization of the new mixing matrix. We begin by studying the bounds obtained from quantities such as Delta M_K, epsilon_K, Delta M_{d/s} as well as sin 2 beta|_{J/psi K_S}, and go on to explore the implications for several clean rare decay channels, namely the decays K+->pi+ nu nu, K_L -> pi0 nu nu, B_{d/s} -> mu+ mu- and K_L -> pi0 l+l-. We find sizeable effects in all these decays, but the most interesting quantity turns out to be the B_s - bar B_s mixing phase beta_s, as measured in the mixing induced CP asymmetry of B_s -> J/psi phi, which can be large. In general, we find effects in purely hadronic channels to be larger than in (semi-)leptonic ones, due to a suppression of the Z'-lepton couplings.