QCD factorizations in gamma* gamma* -> rho rho

Abstract

We calculate the lowest order QCD amplitude, i.e. the quark exchange contribution, to the forward production amplitude of a pair of longitudinally polarized $\rho$ mesons in the scattering of two virtual photons ${\gamma }^{\ast }(Q_1){\gamma }^{\ast }(Q_2)\to {\rho }_L^0{\rho }_L^0$. 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 $\rho$ mesons, whereas the part with longitudinally polarized photons takes the QCD factorized form with the ${\gamma }_L^{\ast }\to {\rho }_L^0$ transition distribution amplitude. Perturbative expressions for these, in general, non-perturbative functions are obtained in terms of the $\rho -$meson distribution amplitude.

References in corpus (4)

• QCD analysis of bar p N -> gamma* pi in the scaling limit
• Hadron annihilation into two photons and backward dVCS in the scaling regime of QCD
• Double diffractive rho-production in gamma^* gamma^* collisions
• Exclusive meson pair production in gamma* gamma scattering at small momentum transfer

Cited by in corpus (9)

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• Saturation effects in exclusive rhoT, rhoL meson electroproduction
• Exclusive Two-Vector-Meson Production from e^+ e^- Annihilation
• BFKL resummation effects in the gamma* gamma* total hadronic cross section
• Diffractive production of two rho^0_L mesons in e^+e^- collisions
• Backward DVCS and Proton to Photon Transition Distribution Amplitudes
• Duality between different mechanisms of QCD factorization in γ^*γcollisions
• Diffraction 2006: Theoretical Summary
• Polarized Structure Functions and Two-Photon Physics at Super-B