SEARCH FOR QCD-INSTANTON INDUCED EVENTS IN DEEP INELASTIC EP SCATTERING AT HERA

摘要

A search for QCD-instanton-induced events in deep inelastic ep scattering has been performed with the ZEUS detector at the HERA collider. A kinematic range defined by cuts on the photon virtuality, Q~2 > 120 GeV~2, and on the Bjorken scaling variable, x > 10~(-3), has been investigated. The QCD-instanton induced events were modelled by the Monte Carlo generator QCDINS. A background-independent, conservative 95% confidence level upper limit for the instanton cross section of 26 pb is obtained.