Hard exclusive processes

We present the theory of hard exclusive processes, at medium and asymptotical energies, illustrated through some selected examples.Comment: 10 pages, 9 figures, Invited review talk presented at the International Symposium on Multiparticle Dynamics (ISMD 2012), 16-21 September 2012, Kielce, Polan

Perturbative QCD in the Regge limit: Prospects at ILC

After recalling the theoretical and experimental status of QCD in the Regge limit and the requirement of high energy scattering process of onium-onium type for testing this limit, we show that the International Linear Collider would be a major step in this field.Comment: invited review talk presented at EDS07, 15 figure

Soft gluon cascades and BFKL equation

In this paper we deal with high energy scattering in the Regge limit, using a soft cascade approach. We derive an evolution equation for the gluon density in soft gluons cascades in the leading logarithmic approximation of perturbative QCD, and show that this equation reproduces BFKL equation in the forward case. The whole cascade is equivalent to a single gluon whose self-energy is responsible for gluon reggeization. The same type of equation is obtained for the QED case.Comment: completely revised and rewritten version, 19 pages, latex file, 6 figures using feynman packag

BFKL resummation effects in exclusive production of rho meson pairs at the ILC

We calculate the Born order cross-section for the exclusive production of rho meson pairs in e+e- scattering in the Regge limit of QCD and we show the feasibility of the measurement of this process at the ILC. We also investigate the leading and next-to-leading order BFKL evolution, making this process a very clean test of the BFKL resummation effects.Comment: Talk given at the Linear Collider Workshop (LCWS07), Hamburg, Germany, May 30-June 3 200

Chiral-odd pion generalized parton distributions beyond leading twist

We define in a systematic way, based on the light-cone collinear factorization method, the chiral-odd generalized parton distributions (GPDs) of a pseudoscalar hadron (such as the pi0) up to twist 5. For that, we introduce the relevant matrix elements for 2-parton non-local operators, as well as matrix elements for 3-parton non-local correlators. Their detailed parametrization is fixed based on parity, charge conjugation and time reversal invariance. This leads to the introduction of 20 real GPDs, whose symmetry properties are explicitely given. The reduction of these GPDs to a minimal set is performed by the use of constraints provided by QCD equations of motion and rotation on the light-cone. We show that these 20 GPDs can be expressed through 8 GPDs which satisfy 4 integral sum rules. A surprising outcome of this analysis is the fact that, when assuming the vanishing of 3-parton correlators, as in the so-called Wandzura-Wilczek approximation, the whole set of GPDs vanishes.Comment: 27 pages, 4 figures, 1 tabl

Mueller Navelet jets at LHC: a clean test of QCD resummation effects at high energy?

Mueller Navelet jets were proposed more than 25 years ago as a decisive test of BFKL dynamics at hadron colliders. We here present a complete next-to-leading BFKL study of the azimuthal decorrelation of these jets. This includes both next-to-leading corrections to the Green's function and next-to-leading corrections to the jet vertices. We compare our results with recent data taken at the LHC and results obtained in a fixed order next-to-leading-order (NLO) calculation.Comment: 9 pages, 7 figures, to appear in the proceedings of XXI International Workshop on Deep-Inelastic Scattering and Related Subject - DIS 2013, 22-26 April 2013, Marseille, Franc

Confronting Mueller-Navelet jets in NLL BFKL with LHC experiments at 7 TeV

More than 25 years ago, Mueller Navelet jets were proposed as a decisive test of BFKL dynamics at hadron colliders. We here study this process at NLL BFKL accuracy, taking into account NLL corrections to the Green's function and to the jet vertices. We present detailed predictions for various observables that can be measured at LHC in ongoing experiments like ATLAS or CMS at sqrt{s}=7 TeV: the cross-section, the azimuthal correlations and the angular distribution of these jets. For this purpose, we apply realistic kinematical cuts and binning, and study the dependence of our results with respect to several parameters. We then compare our results with those that can be obtained in a fixed order NLO treatment, and propose specific observables which could actually be used as a probe of BFKL dynamics.Comment: 30 pages, 25 figure