S, T, U parameters in $SU(3)_C\times SU(3)_L\times U(1)$ model with right-handed neutrinos

TL;DR

This paper calculates the S, T, U electroweak parameters in a specific 3-3-1 model with right-handed neutrinos, providing bounds on bilepton contributions and implications for Z' mass and bilepton mass splitting.

Contribution

It offers explicit formulas for oblique and Z-Z' mixing contributions in the 3-3-1 model, and derives bounds on bilepton parameters and the neutral bilepton mass.

Findings

Bilepton contributions to S and T are bounded within specific ranges.

Z-Z' mixing contribution is positive and increases with Z' mass.

Derived a 15% mass splitting for bileptons and limits on neutral bilepton mass.

Abstract

The S, T, U parameters in the $ SU(3)_C\times SU(3)_L\times U(1)$ model with right -handed neutrinos are calculated. Explicit expressions for the oblique and Z - Z' mixing contributions are obtained. We show that the bilepton oblique contributions to S and T parameters are bounded : $- 0.085 \stackrel{<}{\sim} S \stackrel{<}{\sim} 0.05$ and $- 0.001 \stackrel{<}{\sim} T \stackrel{<}{\sim} 0.08$. The Z - Z' mixing contribution is positive and above 10%, but it will increase fastly with the higher Z' mass. %can be negative. The consequent mass splitting of the bilepton is derived and to be 15%. The limit on the mass of the neutral bilepton in this model is obtained.