Measurement of the inclusive 3-jet production differential cross section in proton-proton collisions at 7 TeV and determination of the strong coupling constant in the TeV range

TL;DR

This study measures the inclusive 3-jet production cross section at 7 TeV using CMS data, compares it with QCD predictions, and extracts the strong coupling constant with improved precision in the TeV range.

Contribution

It provides the first measurement of the 3-jet differential cross section at 7 TeV and determines the strong coupling constant from high-mass jet events.

Findings

Data and theory are in agreement within uncertainties.

The measured strong coupling constant is alpha[S](MZ) = 0.1171 +/- 0.0013 (exp) +0.0073/-0.0047 (theo).

The analysis extends the determination of alpha[S] to the TeV energy scale.

Abstract

This paper presents a measurement of the inclusive 3-jet production differential cross section at a proton-proton centre-of-mass energy of 7 TeV using data corresponding to an integrated luminosity of 5 inverse femtobarns collected with the CMS detector. The analysis is based on the three jets with the highest transverse momenta. The cross section is measured as a function of the invariant mass of the three jets in a range of 445-3270 GeV and in two bins of the maximum rapidity of the jets up to a value of 2. A comparison between the measurement and the prediction from perturbative QCD at next-to-leading order is performed. Within uncertainties, data and theory are in agreement. The sensitivity of the observable to the strong coupling constant alpha[S] is studied. A fit to all data points with 3-jet masses larger than 664 GeV gives a value of the strong coupling constant of alpha[S](MZ) = 0.1171 +/- 0.0013 (exp) +0.0073/-0.0047 (theo).