$SU(3)_c\otimes SU(3)_L\otimes U(1)_X$ models with four families

TL;DR

This paper explores four-family models within the $SU(3)_c imes SU(3)_L imes U(1)_X$ gauge group, identifying anomaly-free structures, analyzing their physical properties, and examining implications for flavor-changing neutral currents in light of LHC data.

Contribution

It identifies and analyzes the simplest anomaly-free four-family models within the $SU(3)_c imes SU(3)_L imes U(1)_X$ framework, including current calculations and flavor physics implications.

Findings

Two realistic anomaly-free models identified

Charged and neutral currents calculated for the simplest model

Potential new flavor-changing neutral currents analyzed

Abstract

In the context of the local gauge group $SU(3)_c\otimes SU(3)_L\otimes U(1)_X$, we look for possible four family models, where all the particles carry ordinary electric charges. Thirteen different anomaly-free fermion structures emerge, out of which only two are realistic. For the simplest physical structure, we calculate the charged and neutral weak currents and the tree-level Fermion masses. We also look for new sources of flavor changing neutral currents in the quark sector, in connection with the upcoming experimental results at the Large Hadron Collider.