# Measurement of the ratio of the inclusive 3-jet cross section to the inclusive 2-jet cross section in pp collisions at sqrt(s) = 7 TeV and first determination of the strong coupling constant in the TeV range

Abstract : A measurement is presented of the ratio of the inclusive 3-jet cross section to the inclusive 2-jet cross section as a function of the average transverse momentum, , of the two leading jets in the event. The data sample was collected during 2011 at a proton-proton centre-of-mass energy of 7 TeV with the CMS detector at the LHC, corresponding to an integrated luminosity of 5.0 inverse femtobarns. The strong coupling constant at the scale of the Z boson mass is determined to be alphaS[MZ] = 0.1148 +/- 0.0014 (exp.) +/- 0.0018(PDF) +0.0050/-0.0000 (scale), by comparing the ratio in the range 0.42 < < 1.39 TeV to the predictions of perturbative QCD at next-to-leading order. This is the first determination of alphaS[MZ] from measurements at momentum scales beyond 0.6 TeV. The predicted ratio depends only indirectly on the evolution of the parton distribution functions of the proton such that this measurement also serves as a test of the evolution of the strong coupling constant beyond 0.42 TeV. No deviation from the expected behaviour is observed.
Document type :
Journal articles

http://hal.in2p3.fr/in2p3-00819068
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Submitted on : Tuesday, April 30, 2013 - 8:16:27 AM
Last modification on : Thursday, October 21, 2021 - 3:56:05 PM

### Citation

S. Chatrchyan, M. Besançon, S. Choudhury, F. Couderc, M. Dejardin, et al.. Measurement of the ratio of the inclusive 3-jet cross section to the inclusive 2-jet cross section in pp collisions at sqrt(s) = 7 TeV and first determination of the strong coupling constant in the TeV range. European Physical Journal C: Particles and Fields, Springer Verlag (Germany), 2013, 73, pp.2604. ⟨10.1140/epjc/s10052-013-2604-6⟩. ⟨in2p3-00819068⟩

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