Measurement of the ratio of the inclusive 3-jet cross section to the inclusive 2-jet cross section in pp collisions at and first determination of the strong coupling constant in the TeV range

Chatrchyan, S. and Khachatryan, V. and Sirunyan, A. M. and Tumasyan, A. and Adam, W. and Bergauer, T. and Dragicevic, M. and Erö, J. and Fabjan, C. and Friedl, M. and Frühwirth, R. and Ghete, V. M. and Hörmann, N. and Hrubec, J. and Jeitler, M. and Kiesenhofer, W. and Knünz, V. and Krammer, M. and Krätschmer, I. and Liko, D. and Mikulec, I. and Rabady, D. and Rahbaran, B. and Rohringer, C. and Rohringer, H. and Schöfbeck, R. and Strauss, J. and Taurok, A. and Treberer-Treberspurg, W. and Waltenberger, W. and Bencze, György and Hajdu, Csaba and Hidas, Pál and Horváth, Dezső and Siklér, Ferenc and Veszprémi, Viktor and Vesztergombi, György and Zsigmond, Anna Júlia and Molnár, József and Pálinkás, József and Karancsi, János and Trócsányi, Zoltán and Ujvári, Balázs and Krajczár, Krisztián and Veres, Gábor (2013) Measurement of the ratio of the inclusive 3-jet cross section to the inclusive 2-jet cross section in pp collisions at and first determination of the strong coupling constant in the TeV range. EUROPEAN PHYSICAL JOURNAL C, 73 (10). ISSN 1434-6044

Preview

Text 1304.7498v2.pdf Available under License Creative Commons Attribution. Download (656kB) | Preview

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, hpT1,2i, 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 fb−1 . The strong coupling constant at the scale of the Z boson mass is determined to be αS(MZ) = 0.1148 ± 0.0014 (exp.) ± 0.0018 (PDF) ± 0.0050 (theory), by comparing the ratio in the range 0.42 < hpT1,2i < 1.39 TeV to the predictions of perturbative QCD at next-to-leading order. This is the first determination of αS(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. No deviation from the expected behaviour is observed.

Actions (login required)

Edit Item