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 $e^{+}{e}^{-}\to \tau e+4jets+\text{E}$ 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.

Comments: 27 pages, 6 figures. A new section added. Conclusion unchanged. To appear in Phys. Rev. D