Measurement of Dijet Angular Distributions and Search for Quark Compositeness

TL;DR

This paper reports measurements of dijet angular distributions in proton-antiproton collisions at 1.8 TeV, confirming QCD predictions and setting limits on quark compositeness scales.

Contribution

The study provides the first measurement of dijet angular distributions at this energy and constrains quark compositeness models with contact interaction scales below 2 TeV.

Findings

QCD predictions agree with data

Excluded quark compositeness models below 2 TeV

Provided new limits on quark substructure

Abstract

We have measured the dijet angular distribution in $\sqrt{s}$=1.8 TeV $p\bar{p}$ collisions using the D0 detector. Order $\alpha^{3}_{s}$ QCD predictions are in good agreement with the data. At 95% confidence the data exclude models of quark compositeness in which the contact interaction scale is below 2 TeV.