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

Abstract

AbstractThe azimuthal correlation, $$\Delta \phi _{12}$$ Δ

ϕ 12

, of high transverse momentum jets in pp collisions at $$\sqrt{s}=13$$

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 $$\Delta \phi _{12}$$

Δ

ϕ 12

is observed. In the back-to-back region of $${\Delta \phi _{12}}\rightarrow \pi $$

Δ

ϕ 12

→ π

, 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 $$\alpha _\mathrm {s}$$

α 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 $$\Delta \phi _{12}$$

Δ

ϕ 12

measurements are also compared with predictions using MCatNLO together Pythia8, illustrating the importance of details of the parton shower evolution.