Related papers: Hard Colour Singlet Exchange at the Tevatron
Large classes of new physics theories predict the existence of new scalar states, commonly dubbed sgluons, lying in the adjoint representation of the QCD gauge group. Since these new fields are expected to decay into colored Standard Model…
We study the signal from the pair production of $t$-squarks at the Tevatron under the assumption that their two-body decay to charginos as well as their three-body decay to $W$ bosons is kinematically forbidden. In this case, the stop…
Diffractive events are studied by means of identification of one or more rapidity gaps and/or a leading antiproton. Measurements of soft and hard diffractive processes have been performed at the Tevatron $p\bar p$ collider and presented. We…
The started LHC heavy ion program makes it possible to probe new frontiers of the high temperature Quantum Chromodynamics. It is expected that the role of hard and semi-hard particle production processes may be significant at ultra-high…
The forward-backward asymmetry for top quarks measured in proton-antiproton collisions at the Tevatron shows an interesting deviation from standard model expectations. Among possible interpretations, the exchange of a non-universal,…
The topical subject of Higgs production in diffractive hard scattering events at the Tevatron and LHC is discussed. This has been proposed as a Higgs discovery channel with appealing experimental features. Predictions are obtained from the…
A search is presented for exotic processes that result in final states containing jets including at least one b jet, sizable missing transverse momentum, and a pair of leptons with the same electric charge. Using a sample of 14.3 fb^-1 of…
Recent results on diffraction at HERA, from the H1 and ZEUS Collaborations, and at Tevatron, from the CDF and D0 Collaborations, are reviewed. The measurement of the diffractive structure function at HERA is presented, and the pomeron…
Hard probes - final state particles related to an interaction with large momentum transfer or mass scale - play a distinguished role in the discovery and the study of the Quark-Gluon Plasma (QGP), a phase of deconfined quarks and gluons…
The success of recently proposed models for describing rapidity-gap events in DIS at HERA, in terms additional colour exchange between the struck system and the proton remnant in boson-gluon fusion events, are found to rely heavily on the…
We report a search for large extra spatial dimensions in $p\bar{p}$ collisions at a center of mass energy of 1.8 TeV at the Tevatron. We present recent D0 results on graviton-mediated exchange processes, using events containing a pair of…
Beam-beam forces and collision optics can strongly affect beam lifetime, dynamic aperture, and halo formation in particle colliders. Extensive analytical and numerical simulations are carried out in the design and operational stage of a…
The diffractive photon production at large momentum transfer and large energies is a probe of the parton dynamics of the diffractive exchange. In this paper we revisit the leading order (LO) BFKL equation approach for this process and…
Jets observed in hadron-hadron scattering contain a contribution from the underlying event that is produced by spectator interactions taking place incoherently with the major parton-parton collision, due to the extended composite structure…
We propose that measuring the $Q^2$ dependence of the number of final-state interactions of the recoil protons in quasi-elastic electron scattering from light nuclei is a new method to investigate Color Coherent effects at {\bf…
The HERA diffractive structure function data are interpreted in terms of `diffractive parton distributions' which satisfy DGLAP evolution. These distributions are modeled assuming that the scattering takes place off a colour singlet…
The perturbative QCD description of high-energy hadroproduction of two hard jets separated by a large rapidity gap void of emission (also called Mueller-Tang jets) is based on a factorization formula of BFKL type that represents exchanges…
The class of semi-hard reactions represents a promising venue where to enhance our knowledge of strong interactions and deepen the aspects related to this theory in kinematical regimes so far unexplored. In particular, the high energies…
The recently reported excess of events at HERA compared to QCD calculations impels us to examine all possible Standard Model explanations before invoking ``new physics''. We explore the possibility of adding an unusual, but small, component…
We discuss the implications of rapid (few-minute) variability in the TeV flux of blazars, which has been observed recently with the HESS and MAGIC telescopes. The variability timescales seen in PKS 2155-304 and Mrk 501 are much shorter than…