Light-by-light scattering in Double-Logarithmic Approximation

Abstract

In the present paper we consider the elastic 2 -> 2 -scattering of virtual photons at high energies in the forward kinematics at zero and non-zero values of t. Accounting for both gluon and quark double-logarithmic (DL) contributions to all orders in the QCD coupling, we obtain explicit expressions for amplitudes of this process in Double-Logarithmic Approximation (DLA). First we keep the QCD coupling fixed and then account for running coupling effects. Applying the saddle-point method to the obtained expressions for the scattering amplitude, we calculate the high-energy asymptotics of the amplitude, which proved to be of the Regge form. The Reggeon bears the vacuum quantum numbers and therefore it is a new, DL contribution to Pomeron. Comparison of the DL Pomeron to the BFKL Pomeron shows that contribution of the DL Pomeron to the high-energy asymptotics is of the same order as contribution of the BFKL Pomeron, so the DL Pomeron should be taken into account together with the BFKL Pomeron. We estimate the applicability region for the asymptotics of the light-by-light scattering amplitude, where the the DL Pomeron can reliably represent the parent amplitude.

16 pages, 4 figures. Multiple errors are corrected, 2 figs are added, comparizon to BFKL is done in more detail

References in corpus (5)

• Electroproduction of two light vector mesons in next-to-leading BFKL: study of systematic effects
• BFKL resummation effects in the gamma* gamma* total hadronic cross section
• ${\gamma }^{\ast }{\gamma }^{\ast }$ Cross Section at NLO and Properties of the BFKL Evolution at Higher Orders
• The ${\gamma }^{\ast }{\gamma }^{\ast }$ total cross section in next-to-leading order BFKL and LEP2 data
• Elastic scattering of virtual photons via quark loop in Double-Logarithmic Approximation

Cited by in corpus (3)

• Hunting BFKL in semi-hard reactions at the LHC
• Combining the small-x evolution and DGLAP for description of inclusive photon induced processes
• NNLO QCD corrections to $\gamma \gamma \to Q\bar{Q}$ from Local Unitarity combined with Coulomb resummation and NLO EW effects