New determination of the Pomeron intercept in hard processes

Abstract

A method allowing for a direct comparison of data with theoretical predictions is proposed for forward jet production at DESY HERA. It avoids the reconstruction of multiparton contributions by expressing the experimental cuts directly as correction factors on the QCD forward jet cross section. An application to the determination of the effectivePomeron intercept in the Balitskii-Fadin-Kuraev-Lipatov (BFKL)--leading-order (LO) parametrization from $d\ensuremath{\sigma}/dx$ data at HERA leads to a good fit with a significantly higher effectiveintercept, ${\ensuremath{\alpha}}_{P}=1.43\ifmmode\pm\else\textpm\fi{}0.025(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.025(\mathrm{syst}),$ than for proton (total and diffractive) structure functions. It is, however, less than the value of the Pomeron intercept using dijets with large rapidity intervals obtained at the Fermilab Tevatron. We also evaluate the rapidity veto contribution to the higher-order BFKL corrections. The method can be extended to other theoretical inputs.