Search for Excited Leptons at HERA

TL;DR

This paper reports on a search for excited electrons and neutrinos using the full HERA data, setting new limits on their possible masses and couplings in the absence of a detected signal.

Contribution

It provides the most comprehensive limits to date on excited leptons at HERA, extending the excluded mass and coupling regions beyond previous experiments.

Findings

No evidence of excited leptons was observed.

New exclusion limits on the ratio of coupling to compositeness scale were established.

The search covered higher mass ranges than prior studies.

Abstract

Searches for excited electrons and neutrinos have been performed using the complete HERA I and II data samples collected by the H1 detector at $\sqrt{s}=320$ GeV corresponding to an integrated luminosity of up to 435 pb$^{-1}$. In absence of a signal, the limits on the ratio of the coupling to the compositeness scale derived extend the excluded region to higher masses than has been possible in previous searches.