Azimuthal correlations of high transverse momentum jets at next-to-leading order in the parton branching method

TL;DR

This paper investigates azimuthal correlations of high transverse momentum jets at 13 TeV using NLO calculations with PB-TMD distributions, highlighting the importance of soft-gluon coupling in angular evolution and comparing different TMD sets.

Contribution

It demonstrates the effectiveness of PB-TMD distributions in describing jet azimuthal correlations at NLO and emphasizes the significance of the evolution scale choice in parton shower modeling.

Findings

Good agreement with PB-TMD Set 2 in the back-to-back region.

Scale uncertainties dominate the total prediction uncertainties.

Parton shower details significantly affect the correlation predictions.

Abstract

The azimuthal correlation, $\Delta \phi_{12}$, of high transverse momentum jets in pp collisions at $\sqrt{s}=13$ TeV is studied by applying PB-TMD distributions to NLO calculations via MCatNLO together with the PB-TMD parton shower. A very good description of the cross section as a function of $\Delta \phi_{12}$ is observed. In the back-to-back region of $\Delta \phi_{12} \to \pi$, a very good agreement is observed with the PB-TMD Set 2 distributions while significant deviations are obtained with the PB-TMD Set 1 distributions. Set 1 uses the evolution scale while Set 2 uses transverse momentum as an argument in $\alpha_s$, and the above observation therefore confirms the importance of an appropriate soft-gluon coupling in angular ordered parton evolution. The total uncertainties of the predictions are dominated by the scale uncertainties of the matrix element, while the uncertainties coming from the PB-TMDs and the corresponding PB-TMD shower are very small. The $\Delta \phi_{12}$ measurements are also compared with predictions using MCatNLO together PYTHIA8, illustrating the importance of details of the parton shower evolution.