Measurement of Dijet Azimuthal Decorrelations at Central Rapidities in pp-bar Collisions at sqrt(s)=1.96 TeV

Abstract

Correlations in the azimuthal angle between the two largest transverse momentum jets have been measured using the D0 detector in pp-bar collisions at a center-of-mass energy sqrt(s)=1.96 TeV. The analysis is based on an inclusive dijet event sample in the central rapidity region corresponding to an integrated luminosity of 150 pb-1. Azimuthal correlations are stronger at larger transverse momenta. These are well-described in perturbative QCD at next-to-leading order in the strong coupling constant, except at large azimuthal differences where soft effects are significant.

Figures (3)

• Figure 1: The $\Delta \phi\,{}_{\text{dijet}}$ distributions in four regions of $p_T^{{\text{max}}}$. Data and predictions with $p_T^{{\text{max}}} > 100\,\text{GeV}$ are scaled by successive factors of 20 for purposes of presentation. The solid (dashed) lines show the NLO (LO) pQCD predictions.
• Figure 2: Ratios of data to the NLO pQCD calculation for different regions of $p_T^{{\text{max}}}$. Theoretical uncertainties due to variation of $\mu_r$ and $\mu_f$ are shown as the shaded regions; the uncertainty due to the PDFs is indicated by the solid lines. The points at large $\Delta \phi\,{}_{\text{dijet}}$ are excluded because the calculation has non-physical behavior near the divergence at $\pi$.
• Figure 3: The $\Delta \phi\,{}_{\text{dijet}}$ distributions in different $p_T^{{\text{max}}}$ ranges. Results from herwig and pythia are overlaid on the data. Data and predictions with $p_T^{{\text{max}}} > 100\,\text{GeV}$ are scaled by successive factors of 20 for purposes of presentation.