CERN-TH-95-84 SHEP 95-14 SEARCH FOR LARGE RAPIDITY GAP EVENTS IN ee ANNIHILATION

We investigate the cross-section for the production of a low-mass coloursinglet cluster in ee annihilation with a large rapidity gap between the colour-singlet cluster and the other jets. It is argued that such events are the cross-channel analogue of large-rapidity-gap events in deep-inelastic scattering, and therefore could in principle be used to investigate the analytic continuation of the BFKL pomeron to the positive-t kinematic regime, where one would expect the trajectory to pass through glueball states. The cross section can be calculated in perturbative QCD, so that the infrared scale arising from non-perturbative e ects, which prevents an exponential fall-o with rapidity gap in the case of deep-inelastic scattering, is absent in ee annihilation. Correspondingly, the cross section for such events decreases rapidly with increasing rapidity gap. CERN-TH-95-84 SHEP 95-14 4 April 1995