Next-to-leading BFKL phenomenology of forward-jet cross sections at HERA

Abstract

We show that the forward-jet measurements performed at HERA allow for a detailed study of corrections due to next-to-leading logarithms (NLL) in the Balitsky-Fadin-Kuraev-Lipatov (BFKL) approach. While the description of the d\sigma/dx data shows small sensitivity to NLL-BFKL corrections, these can be tested by the triple differential cross section d\sigma/dxdk_T^2dQ^2 recently measured. These data can be successfully described using a renormalization-group improved NLL kernel while the standard next-to-leading-order QCD or leading-logarithm BFKL approaches fail to describe the same data in the whole kinematic range. We present a detailed analysis of the NLL scheme and renormalization-scale dependences and also discuss the photon impact factors.

Comments: 15 pages, 9 figures, new title, NLL-BFKL saddle-point approximation replaced by exact integration