B. Pire

Testing the handbag contribution to exclusive virtual Compton scattering

Abstract We discuss the handbag approximation to exclusive deep virtual Compton scattering. After defining the kinematical region where this approximation can be valid, we propose tests for its relevance in planned electroproduction experiments, e + p → e + p + γ . We focus on scaling laws in the cross section, and the distribution in the angle between the lepton and hadron planes, which contains valuable information on the angular momentum structure of the Compton process. We advocate to measure weighted cross sections, which make use of the data in the full range of this angle and do not require very high event statistics.

Hadronic jets with a large Q⊥ lepton pair trigger

Abstract We propose to observe hadron jets in correlation with large Q⊥ transverse momentum lepton pairs. This would allow to test the theoretical idea that the large transverse momentum of the pair is mainly produced through a scattering subprocess a + b → c +γ ∗ . The quantum number content of these jets is a specific signature of the subprocess, especially of those involved in perturbative QCD.

Cross-channel analysis of quark and gluon generalized parton distributions with helicity flip

Quark and gluon helicity flip generalized parton distributions (GPDs) address the transversity quark and gluon structure of the nucleon. In order to construct a theoretically consistent parametrization of these hadronic matrix elements, we work out the set of combinations of those GPDs suitable for the SO(3) partial wave (PW) expansion in the cross-channel. This universal result will help to build up a flexible parametrization of these important hadronic non-perturbative quantities, using, for instance, the approaches based on the conformal PW expansion of GPDs such as the Mellin-Barnes integral or the dual parametrization techniques.

QCD factorizations in gamma* gamma* ---> rho rho

We calculate the lowest order QCD amplitude, i.e. the quark exchange contribution, to the forward production amplitude of a pair of longitudinally polarized

Baryon to meson transition distribution amplitudes and their spectral representation

rho

Pomeron‐Odderon interference in production of π+π− pairs in ultraperipheral collisions

mesons in the scattering of two virtual photons

QCD factorizations in γ ∗ γ ∗ → ρ L 0 ρ L 0

gamma^*(Q_1) gamma^*(Q_2) to rho^0_L rho^0_L

Exclusive hadronization in gamma* gamma -> pi pi

. We show that the scattering amplitude simultaneously factorizes in two quite different ways: the part with transverse photons is described by the QCD factorization formula involving the generalized distribution amplitude of two final

Deeply virtual Compton scattering: How to test handbag dominance?

rho

Off-diagonal helicity density matrix elements for heavy vector mesons inclusively produced in NN,γN and ℓN interactions

mesons, whereas the part with longitudinally polarized photons takes the QCD factorized form with the n