FCNC in the minimal 3-3-1 model revisited

TL;DR

This paper revisits flavor changing neutral currents in the minimal 3-3-1 model, showing that scalar contributions can relax constraints on the $Z'$ mass, allowing it to be lighter than previously believed.

Contribution

It provides a detailed numerical analysis of quark mixing matrices and demonstrates the potential for scalar and vector contributions to interfere, affecting $Z'$ mass constraints.

Findings

Neutral scalar contributions can interfere with $Z'$ effects.

The $Z'$ boson may be lighter than previously constrained.

A range of parameters allows for relaxed FCNC constraints.

Abstract

We show that in the minimal 3-3-1 model the flavor changing neutral currents (FCNCs) do not impose necessarily strong constraints on the mass of the $Z^\prime$ of the model if we also consider the neutral scalar contributions to such processes, like the neutral mesons mass difference and rare semileptonic decays. We first obtain numerical values for all the mixing matrices of the model i.e., the unitary matrices that rotate the left- and right-handed quarks in each charge sector which give the correct mass of all the quarks and the CKM mixing matrix. Then, we find that there is a range of parameters in which the neutral scalar contributions to these processes may interfere with those of the $Z^\prime$, implying this vector boson may be lighter than it has been thought.