Measurement of deep inelastic inclusive and diffractive scattering with Q2 between 25 and 320 GeV2 with the ZEUS Forward Plug Calorimeter at HERA

Deep inelastic scattering and its diffractive component, 
ep -> e'gamma*p -> e'XN, was studied with the ZEUS detector at HERA using 
an integrated luminosity of 52.4 pb-1. The M_X method was used to 
extract the diffractive contribution. A wide range of the centre-of-mass 
energy W (37 - 245GeV), photon virtuality Q2 (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 Q2 increases. The data are also presented in terms of the diffractive 
structure function, F^D(3)_2, of the proton. For fixed Q2 and fixed M_X, 
x_IP F^D(3)_2 shows a strong rise as x_IP -> 0, where x_IP is the fraction of 
the proton momentum carried by the Pomeron.  For Bjorken-x < 10^{-3}, 
x_IP F^D(3)_2 shows positive log Q2 scaling violations, while 
for x > 5 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.