Observation of four top quark production in proton-proton collisions at $\sqrt{s}$ = 13 TeV
Observation of four top quark production in proton-proton collisions at $\sqrt{s}$ = 13 TeV
The observation of the production of four top quarks in proton-proton collisions is reported, based on a data sample collected by the CMS experiment at a center-of-mass energy of 13 TeV in 2016-2018 at the CERN LHC and corresponding to an integrated luminosity of 138 fb$^{-1}$. Events with two same-sign, three, or four charged leptons (electrons and muons) and additional jets are analyzed. Compared to previous results in these channels, updated identification techniques for charged leptons and jets originating from the hadronization of b quarks, as well as a revised multivariate analysis strategy to distinguish the signal process from the main backgrounds, lead to an improved expected signal significance of 4.9 standard deviations above the background-only hypothesis. Four top quark production is observed with a significance of 5.6 standard deviations, and its cross section is measured to be 17.7$^{+3.7}_{-3.5}$ (stat) $^{+2.3}_{-1.9}$ (syst) fb, in agreement with the available standard model predictions.
hep-ex
Belyaev, Alexander
6bdb9638-5ff9-4b65-a8f2-34bae3ac34b3
Belyaev, Alexander
6bdb9638-5ff9-4b65-a8f2-34bae3ac34b3
[Unknown type: UNSPECIFIED]
Abstract
The observation of the production of four top quarks in proton-proton collisions is reported, based on a data sample collected by the CMS experiment at a center-of-mass energy of 13 TeV in 2016-2018 at the CERN LHC and corresponding to an integrated luminosity of 138 fb$^{-1}$. Events with two same-sign, three, or four charged leptons (electrons and muons) and additional jets are analyzed. Compared to previous results in these channels, updated identification techniques for charged leptons and jets originating from the hadronization of b quarks, as well as a revised multivariate analysis strategy to distinguish the signal process from the main backgrounds, lead to an improved expected signal significance of 4.9 standard deviations above the background-only hypothesis. Four top quark production is observed with a significance of 5.6 standard deviations, and its cross section is measured to be 17.7$^{+3.7}_{-3.5}$ (stat) $^{+2.3}_{-1.9}$ (syst) fb, in agreement with the available standard model predictions.
More information
Accepted/In Press date: 22 May 2023
Additional Information:
Submitted to Physics Letters B. All figures and tables can be found at http://cms-results.web.cern.ch/cms-results/public-results/publications/TOP-22-013 (CMS Public Pages)
Keywords:
hep-ex
Identifiers
Local EPrints ID: 478614
URI: http://eprints.soton.ac.uk/id/eprint/478614
PURE UUID: cac14a21-d379-4307-9290-14232ca7cb4f
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Date deposited: 05 Jul 2023 17:34
Last modified: 17 Mar 2024 03:10
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Corporate Author: The CMS Collaboration
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