Related papers: QCD factorization in gamma* gamma -> pi pi and gam…
The exclusive electroproduction of two pions in the mass range 0.4 < M{\pi}{\pi} < 2.5 GeV has been studied with the ZEUS detector at HERA using an integrated luminosity of 82 pb-1. The analysis was carried out in the kinematic range of 2 <…
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…
Experiments at CEBAF will scan the intermediate-energy region of the QCD dynamics for the nucleon form factors and for Compton Scattering. These experiments will definitely clarify the role of resummed perturbation theory and of…
We study the exclusive decay of $1^{--}$ heavy quarkonium into one photon and two pions in the kinematic region, where the two-pion system has a invariant mass which is much smaller than the mass of heavy quarkonium. Neglecting effects…
We propose a new and universal approach to the hadronization problem that incorporates both partonic and hadronic degrees of freedom in their respective domains of relevance, and that describes the conversion between them within a kinetic…
We evaluate Generalized Parton Distributions of the pion in two chiral quark models: the Spectral Quark Model and the Nambu-Jona-Lasinio model with a Pauli-Villars regularization. We proceed by the evaluation of double distributions through…
We present comparisons of high-pT photon and pion production in hadronic interactions with expectations from next-to-leading order perturbative QCD (NLO pQCD). We also comment on phenomenological models of kT smearing (which approximate…
One of the challenging aspects of electroproduction at high-energy is the understanding of the transition from real photons to virtual photons in the GeV^2 region. We study inclusive electroproduction on the proton at small x_B using a…
We show on two examples, namely a calculation for charge symmetry breaking in pn->d pi^0 that allows one to extract the quark mass difference induced part of the proton--neutron mass difference and a high precision calculation for…
We evaluate the amplitude for gamma gamma --> pi^+ pi^- to two loops in the framework of chiral perturbation theory.The three new coupling constants that enter the result at this order in the low-energy expansion are estimated via resonance…
In our work, we describe two types of Compton processes. As an example of an inclusive process, we consider the high-energy photoproduction of massive muon pairs off the nucleon. We analyze the process in the framework of the QCD parton…
Precision computation of hadronic physics with lattice QCD is becoming feasible. The last decade has seen percent-level calculations of many simple properties of mesons, and the last few years have seen calculations of baryon masses,…
We develop an extension of chiral perturbation theory to the $\Delta$(1232)-resonance energy region and apply it to investigate the pion electroproduction off the nucleon ($e^- N \to e^- N\pi$). We present a complete calculation of this…
Generalized parton distributions (GPDs) encoding multidimensional information of hadron partonic structure appear as the building blocks in a factorized description of hard exclusive reactions. The nucleon GPDs have been accessed by deeply…
A simple relativistic model is suggested that elucidates qualitatively the quark-antiquark distribution within virtual photon. The diffractive hadroproduction in DIS initiated by highly virtual photon $\gamma ^{*}(Q^2)$ is discussed in more…
We define in the framework of light-cone collinear factorization method, the chiral-odd generalized parton distributions (GPDs) of a pseudoscalar hadron (such as the $\pi^0$) up to twist 6. For that, we introduce the relevant matrix…
We study inclusive photoproduction of hadrons at HERA via both direct and resolved photons to next-to-leading order (NLO) in the QCD-improved parton model. We predict transverse-momentum ($\pt$) and rapidity ($\ylab$) distributions and…
In this contribution, we discuss a total cross-section model which can be applied to both photon and purely hadronic processes. We find that the model can reproduce photo-production cross-sections, as well as extrapolations of gamma* p…
The exclusive reaction of rho meson pair electroproduction in gamma*gamma* collisions is a nice place to study various dynamics and factorization properties in the perturbative sector of QCD. At low energy (quarks dominance), this process…
In the context of QCD sum rules with non-local condensates we present a pion distribution amplitude, which is double-humped with its end-points x\to(0,1) strongly suppressed, and show that it matches the CLEO experimental data on the…