Production of Jet Pairs at Large Relative Rapidity in Hadron-Hadron Collisions as a Probe of the Perturbative Pomeron

TL;DR

The paper investigates how to test the perturbative pomeron of QCD (BFKL) in hadron-hadron collisions by examining the azimuthal correlation between two jets separated by a large rapidity gap. It develops the BFKL framework for dijet production, derives the all-orders azimuthal distribution F(φ,Δ) via a Fourier expansion, and validates the approach against exact lower-order results. A key finding is that the φ-distribution flattens as Δ grows, signaling decorrelation from multiple soft-gluon emissions, with an analytically tractable large-Δ behavior. The work provides predictions for Tevatron energies and discusses the robustness of the azimuthal observable, suggesting it as a practical probe of BFKL dynamics at current and future colliders (HERA, LHC).

Abstract

The production of jet pairs with small transverse momentum and large relative rapidity in high energy hadron-hadron collisions is studied. The rise of the parton-level cross section with increasing rapidity gap is a fundamental prediction of the BFKL `perturbative pomeron' equation of Quantum Chromodynamics. However, at fixed collider energy it is difficult to disentangle this effect from variations in the cross section due to the parton distributions. It is proposed to study instead the distribution in the azimuthal angle difference of the jets as a function of the rapidity gap. The flattening of this distribution with increasing dijet rapidity gap is shown to be a characteristic feature of the BFKL behaviour. Predictions for the Fermilab proton-antiproton collider are presented.