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$$^* \rightarrow$$f$$\gamma,$$fW,fZ are considered and all possible final states resulting from the Z orW 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.