Probing Left-handed Slepton Flavor Mixing at Future Lepton Colliders

Abstract

It has been argued in the literature that the search for the slepton oscillation phenomenon can be a powerful probe of intergenerational mixing between sleptons, once sleptons are found at future colliders. In this article we estimate possible reach of future lepton colliders in probing left-handed slepton flavor mixing, especially mixing between the first and third generations, on which constraints imposed by other processes like $\tau \to e \gamma$ are very weak. $e^+e^-$ collider is suitable for this purpose, since it can produce, if kinematically allowed, sleptons of the first generation via t-channel, in addition to s-channel. Utilizing $e^+e^- \to \tau e + 4jets + \E$ signal at $e^+e^-$ linear collider with integrated luminosity L=50 fb^{-1}(500 fb^{-1}) it may be possible to reach mixing angle $\sin 2\theta_{\tilde{\nu}} \gtrsim 0.06 (0.04)$ and mass difference $\Delta m_{\tilde{\nu}} \gtrsim 0.07 (0.04)$ GeV for sneutrinos in the first and third generations at the statistical significance of 5 \sigma.