Supersymmetric $W$ Boson Decays as a Means to Search for Charginos and Neutralinos

Abstract

If the sneutrino mass is below the chargino mass, the dominant decay mode of the lightest chargino is via a two-body decay channel ${\chi }_1^{\pm }\text{ra}\tilde{\nu }+l^{\pm }$. Sneutrinos are invisible in $R$-parity conserving supersymmetric models and, if the mass gap $m({\chi }_1^{\pm })-m(\tilde{\nu })$ is sufficiently small, the soft decay lepton may escape detection leading to invisible chargino decays. This ``blind spot'' of the supersymmetry parameter space would jeopardize the chargino search at LEP2. We point out that such a scenario can be tested by searching for single $W$ events in $e^{+}{e}^{-}\text{ra}{W}^{+}{W}^{-}$, with one $W$ boson decaying to visible leptons or quark jets, and the second $W$ boson decaying to invisible charginos and neutralinos.

Comments: LaTeX, 10 pages, 2 figures included, uses epsfig