Measurement of the t t-bar production cross section in the all-jet final state in pp collisions at sqrt(s) = 7 TeV

TL;DR

This paper reports a measurement of the top-antitop quark pair production cross section in the all-jet final state at 7 TeV proton-proton collisions, using CMS data, with results consistent with the Standard Model.

Contribution

First measurement of t t-bar cross section in the all-jet final state at 7 TeV using CMS data, employing a novel background modeling and mass spectrum fitting approach.

Findings

Measured cross section: 139 +/- 10 (stat) +/- 26 (syst) +/- 3 (lum) pb

Results agree with other decay channels and Standard Model predictions

Analysis demonstrates effective background suppression and signal extraction in all-jet topology.

Abstract

A measurement is presented of the t t-bar cross section (sigma[ttbar]) in proton-proton collisions at a centre-of-mass energy of 7 TeV, in the all-jet final state that contains at least six jets, two of which are tagged as originating from b quarks. The data correspond to an integrated luminosity of 3.54 inverse femtobarns, collected with the CMS detector at the LHC. The cross section is determined through an unbinned maximum likelihood fit of background and t t-bar signal to the reconstructed mass spectrum of t t-bar candidates in the data, in which events are subjected to a kinematic fit assuming a t t-bar to W+ b W- b-bar to 6 jets hypothesis. The measurement yields sigma[ttbar] = 139 +/- 10 (stat.) +/- 26 (syst.) +/- 3 (lum.) pb, a result consistent with those obtained in other t t-bar decay channels, as well as with predictions of the standard model.