Hard exclusive two photon processes in QCD

Abstract

This is a short review of some hard two-photon processes: $$\begin{gathered} a)\gamma \gamma \to {\overline{P}}_1{P}_2,{\overline{P}}_1{P}_2=\{{\pi }^{+}{\pi }^{-},K^{+}{K}^{-},K_S{K}_S,{\pi }^o{\pi }^o,{\pi }^o\eta \}, \\ b)\gamma \gamma \to V_1{V}_2,V_1{V}_2=\{{\rho }^o{\rho }^o,\varphi \varphi ,\omega \varphi ,\omega \omega \}, \\ c)\gamma \gamma \to \mathrm{baryon}-\mathrm{antibaryon}, \\ d){\gamma }^{\ast }\gamma \to P^o,P^o=\{{\pi }^o,\eta ,{\eta }^{\prime },{\eta }_c\} \end{gathered}$$. The available experimental data are presented. A number of theoretical approaches to calculation of these processes is described, both those based mainly on QCD and more phenomenological (the handbag model, the diquark model, etc). Some theoretical questions tightly connected with this subject are discussed, in particular: the applications of various types of QCD sum rules, the endpoint behavior of the leading twist meson wave functions, etc.

58 pages, 38 figures, review article; v2: a large number of minor corrections

References in corpus (16)

• Light-Front Dynamics and AdS/QCD Correspondence: The Pion Form Factor in the Space- and Time-Like Regions
• Measurement of gamma gamma* --> pi0 transition form factor at Belle
• Light-cone sum rules for $B\to \pi$ form factors revisited
• Moments of pseudoscalar meson distribution amplitudes from the lattice
• Light Cone Sum Rules for the pi0-gamma*-gamma Form Factor Revisited
• On the Pion Distribution Amplitude Shape
• Lattice Results for Low Moments of Light Meson Distribution Amplitudes
• High-statistics measurement of neutral-pion pair production in two-photon collisions
• High-statistics measurement of neutral-pion pair production in two-photon collisions
• Two Photon Decays of Charmonia from Lattice QCD
• Comparing antithetic trends of data for the pion-photon transition form factor
• Measurement of the gamma gamma* --> eta_c transition form factor
• Measurement of eta eta production in two-photon collisions
• gamma+gamma --> pi+pi, K+K : leading term QCD vs handbag model
• NLO perturbative QCD predictions for gamma gamma -> M+ M- (M=pi,K)
• Selected topics in e^+e^- collisions

Cited by in corpus (3)

• Lattice calculation of the pion transition form factor ${\pi }^0\to {\gamma }^{\ast }{\gamma }^{\ast }$
• Constraining the photon flux in two-photon processes at the LHC
• Charmonium production in ultra-peripheral heavy ion collisions with two-photon processes