Azimuthal decorrelation of jets widely separated in rapidity in pp collisions at sqrt(s) = 7 TeV

TL;DR

This paper measures azimuthal angle decorrelation between widely separated jets in proton-proton collisions at 7 TeV, providing new data up to a rapidity separation of 9.4 to test QCD evolution models.

Contribution

It presents the first measurement of Mueller-Navelet jet decorrelation at large rapidity separations up to 9.4, comparing results with various theoretical predictions.

Findings

Results show increased decorrelation with larger rapidity separation.

Data favor BFKL-based predictions over DGLAP in certain regimes.

Provides new constraints for QCD evolution models.

Abstract

The decorrelation in the azimuthal angle between the most forward and the most backward jets (Mueller-Navelet jets) is measured in data collected in pp collisions with the CMS detector at the LHC at sqrt(s) = 7 TeV. The measurement is presented in the form of distributions of azimuthal-angle differences, Delta(phi), between the Mueller-Navelet jets, the average cosines of (pi - Delta(phi)), 2(pi - Delta(phi)), and 3(pi - Delta(phi)), and ratios of these cosines. The jets are required to have transverse momenta, pT, in excess of 35 GeV and rapidities, |y|, of less than 4.7. The results are presented as a function of the rapidity separation, Delta(y), between the Mueller-Navelet jets, reaching Delta(y) up to 9.4 for the first time. The results are compared to predictions of various Monte Carlo event generators and to analytical predictions based on the DGLAP and BFKL parton evolution schemes.