High-Energy Asymptotics of Photon--Photon Collisions in QCD

Abstract

The high-energy behaviour of the total cross section for highly virtual photons, as predicted by the BFKL equation at next-to-leading order (NLO) in QCD, is presented. The NLO BFKL predictions, improved by the BLM optimal scale setting, are in excellent agreement with recent OPAL and L3 data at CERN LEP2.

Figures (1)

• Figure 1: The energy dependence of the total cross section for highly virtual photon--photon collisions predicted by the NLO BFKL theoryKLPBFKLP01BFKLP compared with OPALOPAL and L3L3 data from LEP2 at CERN. The solid curves correspond to the BLM scale-fixed NLO BFKL predictions. The dashed curve shows the LO BFKL prediction. (Both predictions include the quark-box contribution). The BFKL predictions are shown for two different choices of the Regge scale, LO BFKL: $s_0= Q^2$--$10 Q^2$, NLO BFKL: $s_0=Q^2$--$4 Q^2$.