  A search for QCD-instanton-induced events in deep inelastic ep scattering has
been performed with the ZEUS detector at the HERA collider, using data
corresponding to an integrated luminosity of 38 pb^{-1}. 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, to be compared with the
theoretically expected value of 8.9 pb.
