Measurement of the $b\overline{b}$ dijet cross section in $pp$ collisions at $\sqrt{s} = 7$ TeV with the ATLAS detector

TL;DR

This paper reports a measurement of the $b\overline{b}$ dijet production cross section in proton-proton collisions at 7 TeV using the ATLAS detector, providing detailed differential results and comparisons with QCD predictions.

Contribution

First measurement of $b\overline{b}$ dijet cross section at 7 TeV with detailed differential analysis and comparison to QCD models.

Findings

Measured cross sections as functions of invariant mass, transverse momentum, and angular variables.

Results generally agree with perturbative QCD predictions within uncertainties.

Provides data for testing QCD and improving theoretical models.

Abstract

The dijet production cross section for jets containing a $b$-hadron ($b$-jets) has been measured in proton-proton collisions with a centre-of-mass energy of $\sqrt{s} = 7$ TeV, using the ATLAS detector at the LHC. The data used correspond to an integrated luminosity of 4.2 fb$^{-1}$. The cross section is measured for events with two identified $b$-jets with a transverse momentum $p_T > 20$ GeV and a minimum separation in the $\eta$-$\phi$ plane of $\Delta R = 0.4$. At least one of the jets in the event is required to have $p_T > 270$ GeV. The cross section is measured differentially as a function of dijet invariant mass, dijet transverse momentum, boost of the dijet system, and the rapidity difference, azimuthal angle and angular distance between the $b$-jets. The results are compared to different predictions of leading order and next-to-leading order perturbative quantum chromodynamics matrix elements supplemented with models for parton-showers and hadronization.