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

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.

Comments: Latex, axodraw.sty used, 3 figures, 18 pages