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 GeV(2)) 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), X(P)F(2)(D(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), X(P)F(2)(D(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.