The 2009 Europhysics Conference on High Energy Physics

The production of highly energetic forward neutrons has been studied in deep-inelastic scattering. The data were taken with the H1 detector at HERA in the years 2006-2007 and correspond to an integrated luminosity of 117 pb^-1. Semi-inclusive cross sections have been measured in the kinematic region 4 < Q^2 < 100 GeV^2, 0.7*10^-4 < x < 0.3*10^-1 and the fractional momentum of the neutron 0.3 <...

Exclusive rho^0 electroproduction at HERA has been studied with the ZEUS detector using 120 pb-1 of integrated luminosity collected during 1996-2000. The analysis was carried out in the kinematic range of photon virtuality 2 < Q2 < 160 GeV2, and gamma* p centre-of-mass energy 32 < W < 180 GeV. The results include the Q2 and W dependence of the gamma*p->rho^0 p cross section and the...

The exclusive photoproduction reaction gamma p -> Upsilon p has been studied with the ZEUS experiment in ep collisions at HERA using an integrated luminosity of 468 pb^-1. The measurement covers the kinematic range 60<W<220 GeV and Q^2<1 GeV^2, where W is the photon-proton centre-of-mass energy and Q^2 is the photon virtuality. These results, which represent the analysis of the full ZEUS...

Protons and antiprotons at collider energies are a source of high energy Weizs\"acker--Williams photons. This opens up a possibility to study at the LHC exclusive photoproduction of heavy vector mesons at energies much larger than possible at the HERA accelerator. We present the results of detailed studies of various distributions for the production of heavy quarkonia (e.g. rapidity,...

We calculate several differential distributions for exclusive double diffractive scalar $\chi_c(0^{++})$, axial-vector $\chi_c(1^{++})$ and tensor $\chi_c(2^{++})$ mesons production in the proton-antiproton collisions at Tevatron and in proton-proton collisions at RHIC and LHC. We use the formalism of unintegrated gluon distributions (UGDFs) within the $k_{\perp}$-factorisation approach. The...

Deeply Virtual Compton Scattering is the simplest interaction that allows access to Generalised Parton Distributions, a theoretical framework that can be used to describe the nucleon structure. The strong interest in GPDs results from the fact that they offer access to the total angular momentum of quarks inside the nucleon and to a 3-dimensional picture of nucleon structure. The measurement...

Standard parton distribution functions contain neither information on the correlations between partons nor on their transverse motion, then a vital knowledge about the three dimensional structure of the nucleon is lost. Hard exclusive processes, in particular DVCS, are essential reactions to go beyond this standard picture. In the following, we examine the most recent data in this context and...

We identify the nonlinear evolution equation in impact-parameter space for the ``Supercritical Pomeron'' in Reggeon Field Theory as a 2-dimensional stochastic Fisher-Kolmogorov-Petrovski-Piscounov equation. It exactly preserves unitarity and leads in its radial form to an high energy traveling wave solution corresponding to an ``universal'' behaviour of the impact-parameter...

The experimental evidence for Odderon exchange processes is still weak. In this talk, we will show that the Odderon could be observed by interference effects with the Pomeron in charge asymmetries in the production of two pion pairs. After discussing the theoretical framework for our calculation based on high energy factorization and the necessary phenomenological input, the calculation...