Search for Excited Electrons at HERA

TL;DR

This paper reports a search for excited electrons at HERA, analyzing data from 1994-2000, and sets new exclusion limits on their possible masses and couplings, with no evidence of their existence found.

Contribution

It provides the first comprehensive search for excited electrons at HERA and extends exclusion limits to higher masses than previous experiments.

Findings

No evidence for excited electron production was observed.

New mass-dependent exclusion limits were established.

Limits extend the parameter space beyond previous searches.

Abstract

A search for excited electron e* production is described in which the electroweak decays e*->e gamma, e*->e Z and e*->nu W are considered. The data used correspond to an integrated luminosity of 120 pb^(-1) taken in e^(+-)p collisions from 1994 to 2000 with the H1 detector at HERA at centre-of-mass energies of 300 and 318 GeV. No evidence for a signal is found. Mass dependent exclusion limits are derived for the ratio of the couplings to the compositeness scale, f/Lambda. These limits extend the excluded region to higher masses than has been possible in previous direct searches for excited electrons.