Limits on right-handed charged weak currents from a polarization-asymmetry correlation experiment withIn107

Abstract

A new technique, based on relative measurements of the longitudinal polarization (P) of positrons emitted in two opoosite directions with respect to the nuclear polarization (R=${\mathit{P}}^{\mathrm{-}}$/${\mathit{P}}^{+}$), is used to provide constraints on extensions of the standard model (${\mathit{R}}_0$). The first result, i.e., R/${\mathit{R}}_0$=0.926±0.041, was obtained with ${}_{}{}^{107}{}_{}{}^{}\mathrm{In}$. Interpreted in the framework of left-right symmetric models and assuming no mixing, it provides a 90% C.L. lower limit of 225 GeV/${\mathit{c}}^2$ for the mass of a possible right-handed charged W gauge boson, reducing the mass range allowed by other semileptonic experiments.