Measurement of multi-lepton production with ZEUS at HERA

A search for events with two or more leptons with large transverse
momentum in the final state was performed with the ZEUS detector using
data taken between 1996 and 2007 corresponding to an integrated luminosity
of ~450 pb-1. Both the multi-electron and the multi-muon channels were
investigated.  Total and differential cross sections for multi-lepton 
production  were measured and are compared to the Standard Model predictions.