Search for standard model production of four top quarks in the lepton + jets channel in pp collisions at sqrt(s) = 8 TeV

TL;DR

This paper reports a search for the standard model production of four top quarks in proton-proton collisions at 8 TeV, using the CMS detector, setting an upper limit on the production cross section due to the rarity of the process.

Contribution

First search for four top quark production in the lepton + jets channel at 8 TeV with CMS, employing advanced multivariate techniques to set cross section limits.

Findings

No significant excess observed over SM background

Upper limit of 32 fb on four top quark production cross section

Expected limit was 32 +/- 17 fb

Abstract

A search is presented for standard model (SM) production of four top quarks (t t-bar t t-bar) in pp collisions in the lepton + jets channel. The data correspond to an integrated luminosity of 19.6 inverse femtobarns recorded at a centre-of-mass energy of 8 TeV with the CMS detector at the CERN LHC. The expected cross section for SM four top quark production is approximately 1 fb. A combination of kinematic reconstruction and multivariate techniques is used to distinguish between the small signal and large background. The data are consistent with expectations of the SM, and an upper limit of 32 fb is set at a 95% confidence level on the cross section for producing four top quarks in the SM, where a limit of 32 +/- 17 fb is expected.