Confronting the minimal supersymmetric standard model with the study of scalar leptons at future lineare+e−colliders

Sleptons can easily be found at future linear $e^{+}{e}^{-}$ colliders if kinematically accessible. Measurements of their masses and decay distributions would then determine MSSM parameters. This paper presents a detailed MC study of the production and decay of the lighter scalar $\tau$ lepton ${\tilde{\tau }}_1$, decaying exclusively into the lightest neutralino. We found that $m_{{\tilde{\tau }}_1}$ and ${\theta }_{\tilde{\tau }}$ (the left-right mixing angle of $\tilde{\tau }$) would be measured within an error of a few percent. It is also found that $tan\beta$ is determinable in some region of the parameter space through simultaneous studies of ${\tilde{\tau }}_1$- and $\tilde{e}$-pair production: the polarization measurement of the $\tau$ leptons from ${\tilde{\tau }}_1$ decays and the $M_1$, $m_{{\tilde{\chi }}_1^0}$ determination using ${\tilde{e}}_R$ pair production and decay. We also point out the possibility to determine $g_{\tilde{B}{\tilde{e}}_{R}e}$ through the measurement of the angular distribution of the ${\tilde{e}}_R$-pair production. The error on the coupling is expected to be comparable to its typical SUSY radiative correction, which is proportional to $log\left(\frac{m_{\tilde{q}}}{m_{\tilde{l}}}\right)$. The radiative correction affects $M_1$ and $tan\beta$ determination, necessitating the full one-loop radiative correction to the ${\tilde{e}}_R$ production processes. The implication of these measurements of the MSSM parameters on selecting models of the origin of supersymmetry breaking is also discussed.