TY - JOUR
T1 - Unraveling hadron structure with generalized parton distributions
AU - Belitsky, Andrei
AU - Radyushkin, A. V.
N1 - Funding Information:
This work was supported by the U.S. National Science Foundation under Grant no. PHY-0456520 (A.B.) and by the U.S. Department of Energy contract DE-AC05-84ER40150 under which the Southeastern Universities Research Association (SURA) operates the Thomas Jefferson Accelerator Facility (A.R.). We are honored to dedicate this paper to Anatoly Vasilievich Efremov, our Teacher, who taught us his approach to physical phenomena and guided our first steps in physics. We were lucky to work in the inspiring atmosphere he created in his group, and enjoyed collaboration and discussions with A.V., and our friends, the members of his group, Alexander Bakulev, Eduard Kuraev, Gregory Korchemsky, Sergei Mikhailov, Rusko Ruskov, and Oleg Teryaev. Our work on generalized parton distributions was strongly influenced by our contacts and collaboration with I. Balitsky, V. Braun, K. Goeke, X. Ji, L. Mankiewicz, I. Musatov, D. Müller, M. Polyakov, A. Schäfer, and C. Weiss. One of us (A.B.) expresses his sincere gratitude to Dieter Müller for years of fruitful and inspiring collaboration. Over years, our GPD-effort was generously supported by the Alexander von Humboldt Foundation, and we express our deep gratitude to the Foundation and to our collaborators and colleagues with whom we worked and contacted in Germany: J. Blümlein, D. Diakonov, M. Diehl, Th. Feldmann, A. Freund, B. Geyer, V. Guzey, D. Ivanov, R. Jakob, A. Kirchner, N. Kivel, P. Kroll, M. Lazar, A. Mukherjee, N. Nikolaev, H.-C. Pauli, V. Petrov, G. Piller, P. Pobylitsa, M. Praszalowicz, D. Robaschik, J. Speth, L. Szymanowski, N. Stefanis, W. Schroers, M. Vanderhaeghen, and W. Weise. We thank S.J. Brodsky, M. Burkardt, J.-W. Chen, T. Cohen, J.C. Collins, L. Frankfurt, P. Hoodbhoy, G.P. Korchemsky, R. Lebed, A.D. Martin, G. Miller, B. Pire, M. Ryskin, M. Savage, M. Strikman, B. Tiburzi, and F. Yuan, for numerous stimulating discussions. Last but not least, we are indebted to Markus Diehl, who had generously agreed to be the first reader of this review, for his constructive criticism, numerous suggestions and corrections, which lead to a significant improvement of the manuscript.
PY - 2005/10
Y1 - 2005/10
N2 - The generalized parton distributions, introduced nearly a decade ago, have emerged as a universal tool to describe hadrons in terms of quark and gluonic degrees of freedom. They combine the features of form factors, parton densities and distribution amplitudes-the functions used for a long time in studies of hadronic structure. Generalized parton distributions are analogous to the phase-space Wigner quasi-probability function of nonrelativistic quantum mechanics which encodes full information on a quantum-mechanical system. We give an extensive review of main achievements in the development of this formalism. We discuss physical interpretation and basic properties of generalized parton distributions, their modeling and QCD evolution in the leading and next-to-leading orders. We describe how these functions enter a wide class of exclusive reactions, such as electro- and photo-production of photons, lepton pairs, or mesons. The theory of these processes requires and implies full control over diverse corrections and thus we outline the progress in handling higher-order and higher-twist effects. We catalogue corresponding results and present diverse techniques for their derivations. Subsequently, we address observables that are sensitive to different characteristics of the nucleon structure in terms of generalized parton distributions. The ultimate goal of the GPD approach is to provide a three-dimensional spatial picture of the nucleon, direct measurement of the quark orbital angular momentum, and various inter- and multi-parton correlations.
AB - The generalized parton distributions, introduced nearly a decade ago, have emerged as a universal tool to describe hadrons in terms of quark and gluonic degrees of freedom. They combine the features of form factors, parton densities and distribution amplitudes-the functions used for a long time in studies of hadronic structure. Generalized parton distributions are analogous to the phase-space Wigner quasi-probability function of nonrelativistic quantum mechanics which encodes full information on a quantum-mechanical system. We give an extensive review of main achievements in the development of this formalism. We discuss physical interpretation and basic properties of generalized parton distributions, their modeling and QCD evolution in the leading and next-to-leading orders. We describe how these functions enter a wide class of exclusive reactions, such as electro- and photo-production of photons, lepton pairs, or mesons. The theory of these processes requires and implies full control over diverse corrections and thus we outline the progress in handling higher-order and higher-twist effects. We catalogue corresponding results and present diverse techniques for their derivations. Subsequently, we address observables that are sensitive to different characteristics of the nucleon structure in terms of generalized parton distributions. The ultimate goal of the GPD approach is to provide a three-dimensional spatial picture of the nucleon, direct measurement of the quark orbital angular momentum, and various inter- and multi-parton correlations.
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U2 - 10.1016/j.physrep.2005.06.002
DO - 10.1016/j.physrep.2005.06.002
M3 - Review article
AN - SCOPUS:25444472893
SN - 0370-1573
VL - 418
SP - 1
EP - 387
JO - Physics Reports
JF - Physics Reports
IS - 1-6
ER -