Search for Single Top Quark Production at HERA

TL;DR

This paper reports a search for single top quark production at HERA, setting upper limits on the production cross section and anomalous couplings using a multivariate analysis of the full data sample.

Contribution

First search for single top quark production at HERA using a comprehensive dataset and advanced multivariate techniques.

Findings

Upper limit on cross section: < 0.25 pb at 95% CL

Constraints on anomalous coupling kappa_{tu gamma}

No significant evidence of single top production found

Abstract

A search for single top quark production is performed in the full ep data sample collected by the H1 experiment at HERA, corresponding to an integrated luminosity of 474 pb^-1. Decays of top quarks into a b quark and a W boson with subsequent leptonic or hadronic decay of the W are investigated. A multivariate analysis is performed to discriminate top quark production from Standard Model background processes. An upper limit on the top quark production cross section via flavour changing neutral current processes sigma (ep -> etX) < 0.25 pb is established at 95% CL. Limits on the anomalous coupling kappa_{tu gamma} are derived.