Measurement of the combined rapidity and $p_T$ dependence of dijet azimuthal decorrelations in $p\bar{p}$ collisions at $\sqrt{s}=1.96\,$TeV

TL;DR

This paper measures how the azimuthal angle between dijets varies with rapidity and transverse momentum in proton-antiproton collisions, providing insights into QCD predictions and jet behavior at Tevatron energies.

Contribution

It introduces the first combined measurement of rapidity and $p_T$ dependence of dijet azimuthal decorrelations using the $R_{ riangle m f extphi}$ variable, comparing data with NLO QCD predictions.

Findings

Data agrees with NLO QCD predictions in most regions.

Discrepancies observed at large rapidity intervals and $ riangle m f extphi_{max}$.

Provides new constraints on QCD models of jet decorrelations.

Abstract

We present the first combined measurement of the rapidity and transverse momentum dependence of dijet azimuthal decorrelations, based on the recently proposed quantity $R_{\Delta \phi}$. The variable $R_{\Delta \phi}$ measures the fraction of the inclusive dijet events in which the azimuthal separation of the two jets with the highest transverse momenta is less than a specified value for the parameter $\Delta \phi_{\rm max}$. The quantity $R_{\Delta \phi}$ is measured in $p\bar{p}$ collisions at $\sqrt{s}=1.96\,$TeV, as a function of the dijet rapidity interval, the total scalar transverse momentum, and $\Delta \phi_{\rm max}$. The measurement uses an event sample corresponding to an integrated luminosity of $0.7\,$fb$^{-1}$ collected with the D0 detector at the Fermilab Tevatron Collider. The results are compared to predictions of a perturbative QCD calculation at next-to-leading order in the strong coupling with corrections for non-perturbative effects. The theory predictions describe the data, except in the kinematic region of large dijet rapidity intervals and large $\Delta \phi_{\rm max}$.