HUNTING EFFECTIVE LSPS AT LEP-200

Relatively light sneutrinos, which are experimentally allowed, may sig nificantly affect the currently popular search strategies for supersym metric particles by decaying dominantly into an invisible channel. In certain cases the second lightest neutralino may also decay invisibly leading to two extra carriers of missing energy - in addition to the l ightest supersymmetric particle (LSP) (Z) over tilde(1) - the effectiv e LSPs (ELSPs). It is shown that these ELSPs are allowed in supergravi ty models with common scalar and gaugino masses at the unification sca le for a sizable region of parameter space and are consistent with all constraints derived so far from SUSY searches. The pair production of right handed sleptons, which can very well be the lightest charged SU SY particles in this scenario, at LEP 200 anatheir decay signatures ar e discussed. The signal survives kinematical cuts required to remove t he standard model background. Charginos are also pair produced copious ly if kinematically accessible; they also decay dominantly into hadron ically quiet di-lepton + is not an element of(T) modes leading to inte resting unlike sign dilepton events which are again easily separable f rom the Standard Model backgrounds at LEP 200 energies.