R-PARITY VIOLATION

The occurrence of fixed points in the renormalization group evolution of R-parity-violating (RPV) couplings in the minimum supersymmetric st andard model (MSSM) is quantified, assuming that third generation coup lings are dominant. These fixed points give new upper bounds on the RP V couplings at the electroweak scale. To avoid unacceptable top-quark decays the final-state sparticles participating in these RPV decays mu st have masses greater than or similar to m(t). We also discuss possib le RPV signals at the upgraded LEP collider from pair production and d ecay of the lightest sparticle (expected to be the lightest neutralino but possibly a sneutrino).