A Search for Excited Fermions at HERA

Abstract

A search for excited fermions f^* of the first generation in e^+p scattering at the collider HERA is presented using H1 data with an integrated luminosity of 37 pb^(-1). All electroweak decays of excited fermions, f^* -> f gamma, f W, f Z are considered and all possible final states resulting from the Z or W hadronic decays or decays into leptons of the first two generations are taken into account. No evidence for f^* production is found. Mass dependent exclusion limits on cross-sections and on the ratio of coupling constants to the compositeness scale are derived.