Related papers: Hard diffraction from small-size color sources
I review some of the results presented in the working group on diffraction at DIS97, with a particular emphasis on the theory of diffractive hard scattering.
It is shown, that the hard component of quarks distribution functions induced by instantons gives the essential contribution to hard diffractive processes. We predict large polarization effects in these processes.
The QCD analysis of deep inelastic diffractive scattering is performed assuming the dominance of the "soft" pomeron exchange and simple, physically motivated parametrization of parton distributions in a pomeron. Results of the analysis are…
In a first part, I review our detailed investigation of the prospects to discover deep-inelastic processes induced by small QCD-instantons at HERA. This includes the essence of our calculations based on instanton-perturbation theory,…
The Monte Carlo implementation of different approaches for diffractive scattering in $e - p$ collisions (resolved $\PO$, pQCD, soft color interactions) is described, with emphasis on the construction of the hadronic final state. Simple…
Diffractive processes in photon-proton interactions at HERA offer the opportunity to improve the understanding of the transition between the soft, non-perturbative regime in hadronic interactions at $Q^2 = 0$ and the perturbative region at…
Diffractive scattering involves exchange of a Pomeron to make a rapidity gap. It is normally assumed that to get a hard scattering in diffraction, one may treat the Pomeron as an ordinary particle, which has distributions of gluons and…
The results of experiments at hadron colliders probing the structure of the pomeron through hard diffraction are reviewed. Some results on deep inelastic diffractive scattering obtained at HERA are also discussed and placed in perspective.…
High energy hadronic scattering processes can be described in terms of partonic scattering processes and parton distribution and fragmentation functions. These are bilocal matrix elements of quark operators. Colour gauge-invariance requires…
We discuss diffractive photon-production of vector mesons in holographic QCD. At large $\sqrt{s}$, the QCD scattering amplitudes are reduced to the scattering of pair of dipoles exchanging a closed string or a pomeron. We use the…
We review hard diffractive results and prospects at the Tevatron with an emphasis on factorization breaking in diffractive processes. Upper limits on the exclusive di-jet and chi_c^0 production cross sections at CDF and the status of the D0…
Hard processes leading to high transverse momentum hadron production are calculable in perturbative Quantum Chromodynamics (pQCD) for proton-proton collisions. In heavy-ion collisions, such processes occur as well, and due to a separation…
As an introduction to QCD at the LHC I give an overview of QCD at the Tevatron, emphasizing the high Q^2 frontier which will be taken over by the LHC. After describing briefly the LHC detectors I discuss high mass diffraction, in particular…
Color transparency occurs if a small-sized wave packet, formed in a high momentum transfer process, escapes the nucleus before expanding. The time required for the expansion depends on the masses of the baryonic components of the wave…
In this talk we introduce the main features of a QCD-based model in which the coupling $\alpha_{s}$ is constrained by an infrared mass scale. We show recent applications of this model to hadron-hadron collisions, gap survival probability…
Recent works have discussed the violation of factorization and universality in hadronic hard scattering processes aimed at measurements of T-odd distributions. We use simple arguments to show that it is possible to restore an approximate…
Experimental tests of QCD predictions for event shape distributions combining contributions from hard and soft processes are discussed. The hard processes are predicted by perturbative QCD calculations. The soft processes cannot be…
Quantum chromodynamics (QCD) with a general number of colors, $\Nc$, provides a powerful theoretical laboratory to explore the dynamics of non-Abelian gauge theories. Although $\Nc =3$ does not look a large number, the $1/\Nc$ expansion…
The paper presents the $QCD$ description of the hard and semihard processes in the framework of the Wilson operator product expansion. The smooth transition between the cases of the soft and hard Pomerons is obtained.
Heavy quarkonium production at high transverse momentum ($p_T$) in hadronic collisions is explored in the QCD factorization approach. We find that the leading power in the $1/p_T$ expansion is responsible for high $p_T$ regime, while the…