Search for Excited Electrons in ep Collisions at HERA

Abstract

A search for excited electrons is performed using the full $e^{\pm }p$ data sample collected by the H1 experiment at HERA, corresponding to a total luminosity of 475 pb${}^{-1}$. The electroweak decays of excited electrons $e^{\ast }\to e\gamma$, $e^{\ast }\to eZ$ and $e^{\ast }\to \nu W$ with subsequent hadronic or leptonic decays of the $W$ and $Z$ bosons are considered. No evidence for excited electron production is found. Mass dependent exclusion limits on $e^{\ast }$ production cross sections and on the ratio $f/\Lambda$ of the coupling to the compositeness scale are derived within gauge mediated models. These limits extend the excluded region compared to previous excited electron searches. The $e^{\ast }$ production via contact interactions is also addressed for the first time in $ep$ collisions.

19 pages, 4 figures