Measurement of neutral current e±p cross sections at high Bjorken x with the ZEUS detector

Abstract

The neutral current e ± p cross section has been measured up to values of Bjorken x ∼ = 1 with the ZEUS detector at HERA using an integrated luminosity of 187 pb −1 of e − p and 142 pb −1 of e + p collisions at √ s = 318 GeV. Differential cross sections in x and Q 2 , the exchanged boson virtuality, are presented for Q 2 ≥ 725 GeV 2 . An improved reconstruction method and greatly increased amount of data allows a finer binning in the high-x region of the neutral current cross section and leads to a measurement with much improved precision compared to a similar earlier analysis. The measurements are compared to Standard Model expectations based on a variety of recent parton distribution functions.