Diffractive Higgs boson production at the Fermilab Tevatron and the CERN Large Hadron Collider

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 DESY HERA and the Fermilab Tevatron, we find that only a few diffractive Higgs events may be produced at the Tevatron, but we predict a substantial rate at the CERN Large Hadron Collider.     

Probing top anomalous couplings at the Tevatron and the Large Hadron Collider

Chromomagnetic and chromoelectric dipole interactions of the top quark are studied in a model-independent framework. Limits are set on the scale of new physics that might lead to such contributions using latest Tevatron measurements of the t[`(t)]t{bar t} cross-section. It is demonstrated that the invariant mass distribution is a sensitive probe. Prospects at the LHC are examined. It is shown that, for unitarized amplitudes, an increase in the LHC energy is of little importance, while the accumulation of luminosity plays a crucial role.     

Multi-photon signatures at the Fermilab Tevatron

Fermiophobic Higgs bosons (h_f) exhibiting large branching ratios for decay to two photons can arise in models with two or more scalar doublets and/or triplets. In such models the conventional production mechanisms at hadron colliders, which rely on the h_fVV coupling (V=W,Z), may be rendered ineffective due to severe mixing angle suppression. In this scenario, double h_f production may proceed via the complementary mechanism qq’→H^±h_f with subsequent decay H^±→h_fW^*, leading to events with up to four photons. We perform a simulation of the detection prospects of h_f in the multi-photon (>3) channel at the Fermilab Tevatron and show that a sizeable region of the (m_H±,m_hf) parameter space can be probed during Run II.     

Four jet production at the Tevatron Collider

We present predictions for four-jet production at the Tevatron Collider. The standard QCD production of four-jet final states through 2→4-parton processes is compared to the double-parton scattering production.     

Double diffraction dissociation at the Fermilab Tevatron collider

We present results from a measurement of double diffraction dissociation in pp collisions at the Fermilab Tevatron collider. The production cross section for events with a central pseudorapidity gap of width Deltaeta(0)>3 (overlapping eta = 0) is found to be 4.43+/-0.02(stat)+/-1.18(syst) mb [ 3.42+/-0.01(stat)+/-1.09(syst) mb] at square root of (s) = 1800[630] GeV. Our results are compared with previous measurements and with predictions based on Regge theory and factorization.