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

A model for parton distributions in hadrons

The non-perturbative parton distributions in hadrons are derived from simple physical arguments resulting in an analytical expression for the valence parton distributions. The sea partons arise mainly from pions in hadronic fluctuations. The model gives new insights and a good description of structure function data.Comment: 3 pages, 4 figures, LaTeX. Contribution to DIS 99 worksho

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

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

A model for the parton distributions in hadrons

A simple model is presented for the parton distributions in hadrons. The parton momenta in the hadron rest frame are derived from a spherically symmetric, Gaussian, distribution having a width motivated by the Heisenberg uncertainty relation applied to the hadron size. Valence quarks and gluons originate from the `bare' hadron, while sea partons arise mainly from pions in hadronic fluctuations. Starting from a low Q^2 scale, the distributions are evolved with next-to-leading order DGLAP and give the proton structure function F2(x,Q^2) in good agreement with deep inelastic scattering data.Comment: 12 pages, Latex, 5 figures. Added discussion on the applicability of the model at small Q^2. Figure 3 modified to show smaller Q^

Diffractive Higgs boson production at the Tevatron and LHC

Improved possibilities to find the Higgs boson in diffractive events, having less hadronic activity, depend on whether the cross section is large enough. Based on the soft color interaction models that successfully describe diffractive hard scattering at HERA and the Tevatron, we find that only a few diffractive Higgs events may be produced at the Tevatron, but we predict a substantial rate at the LHC.Comment: 4 pages, 4 figures, uses Revtex

Rapidity gaps at HERA and the Tevatron from soft colour exchanges

Models based on soft colour exchanges to rearrange colour strings in the final state provide a general framework for both diffractive and non-diffractive events in ep and hadron-hadron collisions. We study two such models and find that they can reproduce rapidity gap data from both HERA and the Tevatron. We also discuss the influence of parton cascades and multiple interactions on the results.Comment: 4 pages, 4 EPS figures, presented at UK Phenomenology Workshop on Collider Physics, Durham. Uses iopart.cl