LEPTOQUARK MASS LIMITS FROM SINGLE LEPTOQUARK PRODUCTION AT LEP AND LEP200

We investigate the discovery potential for first generation leptoquark s at the LEP and LEP200 e(+)e(-) colliders. We consider single leptoqu ark production via resolved photon contributions which offers a much h igher kinematic limit than the more commonly considered leptoquark pai r production process. This process also has the advantage that it is i ndependent of the leptoquark chirality, is almost insensitive to wheth er the Leptoquark is scalar or vector, and only depends on the leptoqu ark charge. We estimate that from the nonobservation of energetic e - jet events that cannot be explained as backgrounds, the limits at LEP for all types of leptoquarks are M(LQ) > 90 GeV. For the just complete d root s = 161 GeV run at LEP200 we estimate potential scalar leptoqua rk mass limits of M(LQ) > 130 GeV for Q(LQ) = -2/3, -4/3 and M(LQ) > 1 48 GeV for Q(LQ) = -1/3, -5/3 and for vector LQ's the limits are simil ar to 140 and similar to 154 GeV respectively. Ultimately, LEP200 shou ld be able to achieve discovery limits for leptoquarks of similar to 1 88 GeV for the root s = 190 GeV runs. In all cases we assume electroma gnetic strength coupling.