Measurement of high-Q^{2} neutral-current e^+p deep inelastic scattering cross-sections at HERA

The neutral-current deep inelastic scattering differential cross-sections , for GeV, and , for , 2500 and 10000 GeV, have been measured with the ZEUS detector at HERA. The data sample of 47.7 pb was collected at a center-of-mass energy of 300 GeV. The cross-section, , falls by six orders of magnitude between and 40000 GeV. The predictions of the Standard Model are in very good agreement with the data. Complementing the observations of time-like contributions to fermion-antifermion annihilation, the data provide direct evidence for the presence of exchange in the space-like region explored by deep inelastic scattering. Received: 18 May 1999 / Published online: 3 August 1999