Rapidity gap in the final state hadron distribution in deep inelastic electron scattering at HERA

Abstract

The rapidity space available for hadron production in electron-proton interactions at HERA is 11.4 units in width. In such a space the separation of virtual photon fragmentation from proton fragmentation is observed in events where the invariant mass of the final state hadronic system, W, is greater than 130 Ge V. Experimental cross sections for the virtual photon fragmentation process are presented. A new class of events is identified, where only virtual photon fragmentation and no proton fragmentation is observed. In the final state hadronic system of these events a rapidity gap over four units in width was discovered. Cross sections for these events are also presented, and comparisons are made with the theoretical predictions of the pomeron and hard diffraction models.