Constraints on Z1-Z2 Mixing from the Decay $Z1 \to e-e+$ in the left-right Symmetric Model

Abstract

We examine the decay of $Z_1$ in electrons with recent data from LEP. The partial width $Γ(Z_1\to e^-e^+)$ is studied in the framework of a left-right symmetric model with standard electroweak corrections. Processes measured near the resonance has served to measure the neutral coupling constants very precisely, which is useful to set bounds on the parameters of the model. This partial decay occurs in the resonance zone. As a consecuence the process is independent of the mass of the additional $Z_2$ heavy gauge boson which appears in this kind of models and so we have the mixing angle $\f$ between the left and the right bosons as the only additional parameter. In this paper we take advantage of this fact to set a bound for $\f$: $-9\times 10^{-3}\leq\f\leq 4\times 10^{-3}$, which is in agreement with other constraints previously reported.