Deep inelastic inclusive and diffractive scattering at image values from 25 to 320 GeV2 with the ZEUS forward plug calorimeter Original Research Article

Deep inelastic scattering and its diffractive component, image, have been studied at HERA with the ZEUS detector using an integrated luminosity of 52.4 pb−1. The image method has been used to extract the diffractive contribution. A wide range in the centre-of-mass energy W (37–245 GeV), photon virtuality image (20–450 GeV2) and mass image (0.28–35 GeV) is covered. The diffractive cross section for image rises strongly with W, the rise becoming steeper as image increases. The data are also presented in terms of the diffractive structure function, image, of the proton. For fixed image and fixed image, image shows a strong rise as image, where image is the fraction of the proton momentum carried by the pomeron. For Bjorken-image, image shows positive image scaling violations, while for image negative scaling violations are observed. The diffractive structure function is compatible with being leading twist. The data show that Regge factorisation is broken.