Observation of $$ t\overline{t} $$ production in the lepton+jets and dilepton channels in p+Pb collisions at $$ \sqrt{s_{\textrm{NN}}} $$ = 8.16 TeV with the ATLAS detector



Aad, G, Aakvaag, E, Abbott, B, Abdelhameed, S, Abeling, K, Abicht, NJ, Abidi, SH, Aboelela, M, Aboulhorma, A, Abramowicz, H
et al (show 2892 more authors) (2024) Observation of $$ t\overline{t} $$ production in the lepton+jets and dilepton channels in p+Pb collisions at $$ \sqrt{s_{\textrm{NN}}} $$ = 8.16 TeV with the ATLAS detector. Journal of High Energy Physics, 2024 (11). 101-. ISSN 1126-6708, 1029-8479

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Abstract

<jats:title>A<jats:sc>bstract</jats:sc> </jats:title> <jats:p>This paper reports the observation of top-quark pair production in proton-lead collisions in the ATLAS experiment at the Large Hadron Collider. The measurement is performed using 165 nb<jats:sup> <jats:italic>−</jats:italic>1</jats:sup> of <jats:italic>p</jats:italic>+Pb data collected at <jats:inline-formula> <jats:alternatives> <jats:tex-math>$$ \sqrt{s_{\textrm{NN}}} $$</jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:msub> <mml:mi>s</mml:mi> <mml:mi>NN</mml:mi> </mml:msub> </mml:msqrt> </mml:math> </jats:alternatives> </jats:inline-formula> = 8<jats:italic>.</jats:italic>16 TeV in 2016. Events are categorised in two analysis channels, consisting of either events with exactly one lepton (electron or muon) and at least four jets, or events with two opposite-charge leptons and at least two jets. In both channels at least one <jats:italic>b</jats:italic>-tagged jet is also required. Top-quark pair production is observed with a significance over five standard deviations in each channel. The top-quark pair production cross-section is measured to be <jats:inline-formula> <jats:alternatives> <jats:tex-math>$$ {\sigma}_{t\overline{t}}=58.1\pm 2.0{\left(\textrm{stat}.\right)}_{-4.4}^{+4.8}\left(\textrm{syst}.\right) $$</jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>σ</mml:mi> <mml:mrow> <mml:mi>t</mml:mi> <mml:mover> <mml:mi>t</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>58.1</mml:mn> <mml:mo>±</mml:mo> <mml:mn>2.0</mml:mn> <mml:msubsup> <mml:mfenced> <mml:mrow> <mml:mtext>stat</mml:mtext> <mml:mo>.</mml:mo> </mml:mrow> </mml:mfenced> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>4.4</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>4.8</mml:mn> </mml:mrow> </mml:msubsup> <mml:mfenced> <mml:mrow> <mml:mtext>syst</mml:mtext> <mml:mo>.</mml:mo> </mml:mrow> </mml:mfenced> </mml:math> </jats:alternatives> </jats:inline-formula> nb, with a total uncertainty of 9%. In addition, the nuclear modification factor is measured to be <jats:inline-formula> <jats:alternatives> <jats:tex-math>$$ {R}_{p\textrm{A}}=1.090\pm 0.039{\left(\textrm{stat}.\right)}_{-0.087}^{+0.094}\left(\textrm{syst}.\right) $$</jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>R</mml:mi> <mml:mrow> <mml:mi>p</mml:mi> <mml:mi>A</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>1.090</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.039</mml:mn> <mml:msubsup> <mml:mfenced> <mml:mrow> <mml:mtext>stat</mml:mtext> <mml:mo>.</mml:mo> </mml:mrow> </mml:mfenced> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.087</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.094</mml:mn> </mml:mrow> </mml:msubsup> <mml:mfenced> <mml:mrow> <mml:mtext>syst</mml:mtext> <mml:mo>.</mml:mo> </mml:mrow> </mml:mfenced> </mml:math> </jats:alternatives> </jats:inline-formula>. The measurements are found to be in good agreement with theory predictions involving nuclear parton distribution functions.</jats:p>

Item Type: Article
Uncontrolled Keywords: 5106 Nuclear and Plasma Physics, 5107 Particle and High Energy Physics, 51 Physical Sciences
Divisions: Faculty of Science and Engineering
Faculty of Science and Engineering > School of Physical Sciences
Depositing User: Symplectic Admin
Date Deposited: 29 Nov 2024 16:47
Last Modified: 19 Mar 2025 00:37
DOI: 10.1007/jhep11(2024)101
Open Access URL: https://link.springer.com/article/10.1007/JHEP11(2...
Related Websites:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3188947