Deep inelastic inclusive and diffractive scattering at Q(2) values from 25 to 320 GeV2 with the ZEUS forward plug calorimeter

Deep inelastic scattering and its diffractive component, ep -> e' gamma* p -> e' X N, have been studied at HERA with the ZEUS detector using an integrated luminosity of 52.4 pb(-1). The M-X method has been used to extract the diffractive contribution. A wide range in the centre-of-mass energy W (37-245 GeV), photon virtuality Q(2) (20-450 GeV2) and mass M-X (0.28-35 GeV) is covered. The diffractive cross section for 2 < M-X < 15 GeV rises strongly with W, the rise becoming steeper as Q(2) increases. The data are also presented in terms of the diffractive structure function, F-2(D(3)), of the proton. For fixed Q(2) and fixed M-X, XPF2D(3) shows a strong rise as x(P) -> 0, where x(P) is the fraction of the proton momentum carried by the pomeron. For Bjorken-x < 1 x 10(-3), XPF2D(3) shows positive log Q(2) scaling violations, while for x >= 5 x 10(-3) negative scaling violations are observed. The diffractive structure function is compatible with being leading twist. The data show that Regge factorisation is broken.