Anterpreet Kaur

Extraction of the Strong Coupling Constant from the Measurement of Inclusive Multijet Event Cross Sections in pp Collisions at Center of Mass Energy of 8 TeV

A measurement of inclusive multijet event cross sections is presented from proton-proton collisions recorded at 8 TeV with the CMS detector and corresponding to an integrated luminosity of 19.7/fb. Jets are reconstructed with the anti-k\(_{t}\) clustering algorithm for a jet size parameter R \(=\) 0.7 in a phase space region ranging up to jet transverse momenta \(p_\mathrm {T}\) of 2.0 TeV and rapidity of \(|y| < 2.5\). The inclusive 2-jet and 3-jet event cross sections are measured as a function of the average \(p_\mathrm {T}\) of the two leading jets. The results are compared to fixed-order predictions of perturbative QCD and to simulations using various Monte Carlo event generators including parton showers, hadronisation, and multiparton interactions. A fit of the strong coupling constant is performed with the ratio of the 3-jet over 2-jet event cross section.