Measurement of the diffractive cross section in deep inelastic scattering using ZEUS 1994 data

Abstract

Abstract.

The DIS diffractive cross section, , has been measured in the mass range GeV for c.m. energies GeV and photon virtualities to 140 GeV. For fixed and , the diffractive cross section rises rapidly with , with corresponding to a t-averaged pomeron trajectory of which is larger than observed in hadron-hadron scattering. The W dependence of the diffractive cross section is found to be the same as that of the total cross section for scattering of virtual photons on protons. The data are consistent with the assumption that the diffractive structure function factorizes according to . They are also consistent with QCD based models which incorporate factorization breaking. The rise of with decreasing and the weak dependence of on suggest a substantial contribution from partonic interactions.