Search for baryon and lepton number violating Z(0) decays

Using data collected with the OPAL detector at LEP, we have searched for the processes e(+)e(-) --> Z(0) --> pe(-),p mu(-) and the charge conjugate final-states. These would violate the conservation of the baryon-number B, lepton-number L and the fermion-number n = (B + L). No evidence for such decays has been found, and the 95% confidence level upper limits on the partial widths Gamma(Z(0) --> pe) and Gamma(Z(0) --> p mu) are found to be 4.6 and 4.4 keV respectively. (C) 1999 Published by Elsevier Science B.V. All rights reserved.