  A measurement of the double-differential inclusive jet cross section as a
function of the jet transverse momentum pT and the absolute jet rapidity abs(y)
is presented. Data from LHC proton-proton collisions at sqrt(s) = 8 TeV,
corresponding to an integrated luminosity of 19.7 inverse femtobarns, have been
collected with the CMS detector. Jets are reconstructed using the anti-kT
clustering algorithm with a size parameter of 0.7 in a phase space region
covering jet pT from 74 GeV up to 2.5 TeV and jet absolute rapidity up to
abs(y) = 3.0. The low-pT jet range between 21 and 74 GeV is also studied up to
abs(y) = 4.7, using a dedicated data sample corresponding to an integrated
luminosity of 5.6 inverse picobarns. 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 alpha[S(M[Z]) = 0.1164 +0.0060 -0.0043,
where the errors include the PDF, scale, nonperturbative effects and
experimental uncertainties, using the CT10 NLO PDFs. Improved constraints on
PDFs based on the inclusive jet cross section measurement are presented.
