Polarization of $\tau$ lepton from scalar tau decay as a probe of neutralino mixing

Abstract

The $\tau$ lepton arising from the scalar tau ($\text{st}$) decay is naturally polarized. $\text{ptau}$ depends on the left--right mixing of the $\text{st}$ and the gaugino--higgsino mixing of the neutralino. The polarization $\text{ptau}$ could be measured from the energy distribution of the decay products of $\tau$ at future $\text{epem}$ colliders. A measurement of $\text{ptau}$and of the $\text{st}$ production cross section allows to determine both these mixing angles.

Comments: 20 pages Latex, 5 figures(not included). compressed ps file of the figures available at ftp://ftp.kek.jp/kek/preprints/TH/TH-425/fig.ps.gz