Rapidity Gaps in DIS through Soft Colour Interactions

We present a new mechanism for the creation of large rapidity gaps in DIS events at HERA. Soft colour interactions between perturbatively produced partons and colour-charges in the proton remnant, modifies the colour structure for hadronization giving colour singlet systems that are well separated in rapidity. An explicit model is presented that, although the detailed results depend on the initial state parton emission, can describe both the observed rapidity gaps and, in addition, the forward energy flow in an inclusive event sample.Comment: 4 pages Latex, 4 encapsulated Postscript figures, uses qcdparis.sty, tar-compressed and uuencoded with uufiles, Presented by GI at workshop `DIS and QCD', Paris, April 1995, minor Postscript problem fixe

Odderon-Pomeron Interference

We show that the asymmetry in the fractional energy of charm versus anticharm jets produced in high energy diffractive photoproduction is sensitive to the interference of the Odderon $(C = -)$ and Pomeron $(C = +)$ exchange amplitudes in QCD. We predict the dynamical shape of the asymmetry in a simple model and estimate its magnitude to be of the order 15% using an Odderon coupling to the proton which saturates constraints from proton-proton vs. proton-antiproton elastic scattering. Measurements of this asymmetry at HERA could provide firm experimental evidence for the presence of Odderon exchange in the high energy limit of strong interactions.Comment: 12 pages, 4 figures, Minor corrections, Main results unchanged, Contribution from photon exchange added, Numerical estimates updated and uncertainties clarified. To appear in Physics Letters

Rapidity Gaps from Colour String Topologies

Diffractive deep inelastic scattering at HERA and diffractive W and jet production at the Tevatron are well described by soft colour exchange models. Their essence is the variation of colour string-field topologies giving both gap and no-gap events, with a smooth transition and thereby a unified description of all final states.Comment: 3 pages, 6 eps figures, contribution to the DIS 99 workshop proceedings, uses npb.st

Soft Colour Interactions in Non-perturbative QCD

Improved understanding of non-perturbative QCD dynamics can be obtained in terms of soft colour exchange models. Their essence is the variation of colour string-field topologies giving a unified description of final states in high energy interactions. In particular, both events with and without large rapidity gaps are obtained in agreement with data from ep at HERA and ppbar at the Tevatron, where also the surprisingly large production rate of high-p_T charmonium and bottomonium is reproduced.Comment: 4 pages, contribution to PANIC 99 conference proceedings, to appear in Nucl. Phys. A. Uses espcrc1.st

Unified Description of Rapidity Gaps and Energy Flows in DIS Final States

We show that the `orthogonal' characteristics of the observed rapidity gaps and large forward energy flows in deep inelastic scattering at HERA, can be described within a single framework. Our Monte Carlo model is based on perturbative QCD matrix elements and parton showers together with Lund string model hadronization, but has in addition a new mechanism for soft colour interactions which modifies the perturbative colour structure and thereby the hadronization. Effects of perturbative multiparton emission are investigated and the non-perturbative treatment of the proton remnant is discussed and comparison to the observed transverse energy flow is made. We investigate the resulting diffractive-like properties of the model; such as rapidity gap events, $t$- and $M_X$-distributions and the diffractive structure function in comparison to H1 data.Comment: 24 pages LaTeX2e, 13 encapsulated PostScript figure

Soft Colour Interactions as the Origin of Rapidity Gaps in DIS

We introduce soft colour interactions as a novel mechanism to understand the observed events with large rapidity gaps in $ep$ collisions at HERA. Colour exchanges between produced partons and colour-charges in the proton remnant modifies the colour structure for hadronization, such that colour singlet systems may appear well separated in rapidity. Our explicit model show characteristics of diffractive scattering, although no explicit pomeron dynamics have been introduced, and for non-gap events an increased forward energy flow gives agreement with data.Comment: 11 pages Latex, 6 encapsulated Postscript figures, uses revtex.sty, tar-compressed and uuencoded with uufile