Possible sneutrino-pair signatures with R-parity breaking

If sneutrinos are the lightest supersymmetry partners and $R$-parity is not conserved, the process $e^+e^- \to \tilde {\bar\nu} \tilde {\nu}$ can have striking signatures due to the decay modes $\tilde{\nu}\to\ell^+\ell'^-$ or $\tilde{\nu}\to q \bar q'$. We present cross section formulas and discuss event rates and detection at the upgraded $e^+e^-$ collider LEP. Four-lepton signals should be detectable up to sneutrino mass $\tilde {m}_\nu = 80$ GeV and maybe beyond; four-jet signals should be detectable up to $\tilde {m}_\nu = 70$ GeV, but would probably be obscured thereafter by $WW$ background.