Abstract
A measurement of the double-differential inclusive jet cross section as a function of the jet transverse momentum pT and the absolute jet rapidity |y| is presented. Data from LHC proton-proton collisions at $\sqrt{s}=8 TeV$, corresponding to an integrated luminosity of $19.7 fb^{−1}$, have been collected with the CMS detector. Jets are reconstructed using the anti-$k_T$ clustering algorithm with a size parameter of 0.7 in a phase space region covering jet $p_T$ from 74 GeV up to 2.5 TeV and jet absolute rapidity up to |y| = 3.0. The low-$p_T$ jet range between 21 and 74 GeV is also studied up to |y| = 4.7, using a dedicated data sample corresponding to an integrated luminosity of 5.6 $pb^{−1}$. The measured jet cross section is corrected for detector effects and compared with the predictions from perturbative QCD at next-to-leading order (NLO) using various sets of parton distribution functions (PDF). Cross section ratios to the corresponding measurements performed at 2.76 and 7 TeV are presented. From the measured double-differential jet cross section, the value of the strong coupling constant evaluated at the Z mass is $α_S(M_Z) = 0.1164_{− 0.0043}^{+ 0.0060}$, where the errors include the PDF, scale, nonperturbative effects and experimental uncertainties, using the $CT_{10}$ NLO PDFs. Improved constraints on PDFs based on the inclusive jet cross section measurement are presented.
CMS Collaboration