Search for Excited Neutrinos at HERA

TL;DR

This paper reports a search for excited neutrinos in electron-proton collisions at HERA, setting new limits on their properties in unexplored parameter regions.

Contribution

It presents the first search for excited neutrinos at HERA and extends sensitivity beyond previous collider experiments.

Findings

No evidence of excited neutrinos was observed.

New parameter space regions were excluded.

The analysis improves constraints on neutrino compositeness.

Abstract

A search for excited neutrinos produced in electron--proton collisions is performed using a data sample corresponding to an integrated luminosity of 114 pb$^{-1}$ recently collected by the H1 detector at HERA. In absence of a signal, the measurement is interpreted within a minimal model parameterised in terms of couplings and compositness scale. New parameter regions, beyond other colliders sensitivities, are explored by the present preliminary analysis.