Light bottom squarks and gluinos have been invoked to explain the b quark pair production excess at the Fermilab Tevatron. We investigate the associated production of ttbb at hadron colliders in this scenario, and find that the rates for this process are enhanced over the standard model prediction. If light gluinos exist, it may be possible to detect them at the Tevatron, and they could easily ...

We compute the virtual next-to-leading corrections to the impact factors or oo-shell coeecient functions in the high-energy limit, in the helicity-amplitude formalism. These agree with previous results by Fadin and collaborators, in the conventional dimensional-regularization scheme. When combined with the known real corrections, these results will provide the complete NLO corrections to the im...

HIPPOPO (Hadron Induced Particle Production Off Pomeron Outpour) is a program to simulate the production of hadrons via the multipomeron exchange mechanism in a high energy hadron collision. The underlying algorithm is based upon the Quark Gluon String Model developed over the years by many authors [1]-[20]. For the initial colliding beams the User can choose among the following species: nucleo...

Fixed-order QCD perturbation theory fails in some asymptotic regimes where large logarithms multiply the coupling constant. In those regimes resummation of the perturbation series to all orders is necessary to describe many high-energy processes. The Balitsky-FadinKuraev-Lipatov (BFKL) equation 1 performs such a resummation for virtual and real soft gluon emissions in dijet production at large ...

Soft Gluon Effects on Electroweak Boson Production in Hadron Collisions

High energy multiparticle photoproduction off nuclear targets is studied. The photon is assumed to interact in direct scattering processes or as a resolved qq̄-state according to the Generalized Vector Dominance Model. In the description of resolved interactions multiple soft and hard processes in each qq̄-nucleon interaction are taken into consideration. The model, formulated within the framewor...

Our present information on the gluon polarisation ∆g/g is reviewed. The data from fixedtarget lepton–nucleon experiments are in context with the recent data from the RHIC polarised pp collider. The main tools to study ∆g/g in lepton–nucleon scattering are scaling violations of the g1 structure functions and longitudinal spin asymmetries in hadron production. Results from high-pT hadron pairs, i...

The associated production of a J/ψ and a photon in photon-hadron collisions is considered, and shown to be a good probe of the presence of colour-octet mediated channels in quarkonia production, as predicted by the factorization approach within NRQCD. Total and differential cross sections for photoproduction at fixed target experiments and at HERA are presented. Associated J/ψ+ γ production at ...