280 research outputs found
Soft Colour Interactions and Diffractive Hard Scattering at the Tevatron
We make a brief presentation of the soft colour interactions models, the Soft
Colour Interaction and the Generalised Area Law, and summarise the results when
they are applied to p-pbar scattering. The models give a good description of
the Tevatron data on production of W, bottom and jets in diffractive events, as
well as jets with two rapidity gaps, alternatively leading particles. We also
give predictions for diffractive J/psi production and discuss diffractive Higgs
production at the Tevatron and LHC.Comment: 5 pages, 4 figures, uses JHEP style. Talk presented at the
International Europhysics Conference on High Energy Physics (EPS HEP 2001),
Budapest, 12-18 July 200
Testing the dynamics of high energy scattering using vector meson production
I review work on diffractive vector meson production in photon-proton
collisions at high energy and large momentum transfer, accompanied by proton
dissociation and a large rapidity gap. This process provides a test of the high
energy scattering dynamics, but is also sensitive to the details of the
treatment of the vector meson vertex.
The emphasis is on the description of the process by a solution of the
non-forward BFKL equation, i.e. the equation describing the evolution of
scattering amplitudes in the high-energy limit of QCD. The formation of the
vector meson and the non-perturbative modeling needed is also briefly
discussed.Comment: 17 pages, 8 figures. Brief review to appear in Mod. Phys. Lett.
Associated central exclusive production of charged Higgs bosons
We propose central exclusive production of a charged Higgs boson in
association with a W boson as a possible signature of certain types of extended
Higgs sectors. We calculate the cross section and find that the rate at the LHC
could be large enough to allow observation in some models with two Higgs
doublets, where the charged Higgs and at least one of the neutral scalars can
be light enough. We use the two-Higgs doublet model as a prototype and consider
two distinct regions of parameter space, but we also briefly discuss the
prospects for the next-to-minimal supersymmetric standard model, where the
charged Higgs may very well be quite light.Comment: 9 pages, 5 figures. Minor changes, references added. Version to
appear in PR
Vector Meson Photoproduction from the BFKL Equation II: Phenomenology
Diffractive vector meson photoproduction accompanied by proton dissociation
is studied for large momentum transfer. The process is described by the
non-forward BFKL equation which we use to compare to data collected at the HERA
collider.Comment: 39 pages, 29 figure
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
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
Hard colour singlet exchange and gaps between jets at the Tevatron
The new kind of events with a rapidity gap between two high-E_T jets,
observed in high energy ppbar collisions at the Tevatron, is found to be well
described by the exchange of a colour singlet gluon system in the BFKL
framework. This requires going beyond the conventional asymptotic Mueller-Tang
approximation, which results in qualitatively different features of the basic
parton-parton scattering amplitude. Non-leading corrections to the BFKL
equation are included by incorporation of the consistency constraint and the
running QCD coupling. Hadronisation and other non-perturbative QCD effects are
treated through a complete Monte Carlo simulation, providing a gap survival
probability that varies event-by-event, facilitating comparison with
experimental results.Comment: 15 pages, 11 eps figure
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