Eur. Phys. J. C (2008) 55: 259-272
https://doi.org/10.1140/epjc/s10052-008-0587-5

Regular Article - Theoretical Physics

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

¹ IRFU/Service de physique des particules, CEA/Saclay, 91191, Gif-sur-Yvette cedex, France
² RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, NY, 11973, USA
³ Institut de physique théorique, CEA/Saclay, 91191, Gif-sur-Yvette cedex, France
⁴ URA 2306, unité de recherche associée au CNRS, Gif-Sur-Yvette, France

^* e-mail: christophe.royon@cea.fr

Received: 10 December 2007
Revised: 5 March 2008
Published online: 24 April 2008

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 dσ/dx data shows small sensitivity to NLL-BFKL corrections, these can be tested by the triple differential cross section d³σ/dxdk_T ²dQ² 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.