The Azimuthal Decorrelation of Jets Widely Separated in Rapidity

TL;DR

This paper presents the first measurement of azimuthal jet decorrelation over large rapidity gaps at the Fermilab Tevatron, comparing results to QCD predictions and various approximations, revealing discrepancies and agreements.

Contribution

It provides the first experimental measurement of azimuthal jet decorrelation at large rapidity separations and compares these results to multiple QCD-based theoretical models.

Findings

NLO QCD underestimates decorrelation compared to data.

HERWIG Monte Carlo accurately describes the observed decorrelation.

BFKL-based predictions show more decorrelation than observed.

Abstract

This study reports the first measurement of the azimuthal decorrelation between jets with pseudorapidity separation up to five units. The data were accumulated using the D{\O}detector during the 1992--1993 collider run of the Fermilab Tevatron at $\sqrt{s}=$ 1.8 TeV. These results are compared to next--to--leading order (NLO) QCD predictions and to two leading--log approximations (LLA) where the leading--log terms are resummed to all orders in $\alpha_{\scriptscriptstyle S}$. The final state jets as predicted by NLO QCD show less azimuthal decorrelation than the data. The parton showering LLA Monte Carlo {\small HERWIG} describes the data well; an analytical LLA prediction based on BFKL resummation shows more decorrelation than the data.