Differential $$ t\overline{t} $$ cross-section measurements using boosted top quarks in the all-hadronic final state with 139 fb−1 of ATLAS data

Aad, G, Abbott, B, Abbott, DC, Abed Abud, A, Abeling, K, Abhayasinghe, DK, Abidi, SH, Aboulhorma, A, Abramowicz, H, Abreu, H
et al (show 2895 more authors) (2023) Differential $$ t\overline{t} $$ cross-section measurements using boosted top quarks in the all-hadronic final state with 139 fb−1 of ATLAS data. Journal of High Energy Physics, 2023 (4).

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<jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>Measurements of single-, double-, and triple-differential cross-sections are presented for boosted top-quark pair-production in 13 TeV proton–proton collisions recorded by the ATLAS detector at the LHC. The top quarks are observed through their hadronic decay and reconstructed as large-radius jets with the leading jet having transverse momentum (<jats:italic>p</jats:italic><jats:sub>T</jats:sub>) greater than 500 GeV. The observed data are unfolded to remove detector effects. The particle-level cross-section, multiplied by the <jats:inline-formula><jats:alternatives><jats:tex-math>$$ t\overline{t}\to WWb\overline{b} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>t</mml:mi> <mml:mover> <mml:mi>t</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> <mml:mo>→</mml:mo> <mml:mi>WWb</mml:mi> <mml:mover> <mml:mi>b</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math></jats:alternatives></jats:inline-formula> branching fraction and measured in a fiducial phase space defined by requiring the leading and second-leading jets to have <jats:italic>p</jats:italic><jats:sub>T</jats:sub><jats:italic>&gt;</jats:italic> 500 GeV and <jats:italic>p</jats:italic><jats:sub>T</jats:sub><jats:italic>&gt;</jats:italic> 350 GeV, respectively, is 331 <jats:italic>±</jats:italic> 3(stat.) <jats:italic>±</jats:italic> 39(syst.) fb. This is approximately 20% lower than the prediction of <jats:inline-formula><jats:alternatives><jats:tex-math>$$ {398}_{-49}^{+48} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mn>398</mml:mn> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>49</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>48</mml:mn> </mml:mrow> </mml:msubsup> </mml:math></jats:alternatives></jats:inline-formula> fb by P<jats:sc>owheg</jats:sc>+P<jats:sc>ythia</jats:sc> 8 with next-to-leading-order (NLO) accuracy but consistent within the theoretical uncertainties. Results are also presented at the parton level, where the effects of top-quark decay, parton showering, and hadronization are removed such that they can be compared with fixed-order next-to-next-to-leading-order (NNLO) calculations. The parton-level cross-section, measured in a fiducial phase space similar to that at particle level, is 1<jats:italic>.</jats:italic>94 <jats:italic>±</jats:italic> 0<jats:italic>.</jats:italic>02(stat.) <jats:italic>±</jats:italic> 0<jats:italic>.</jats:italic>25(syst.) pb. This agrees with the NNLO prediction of <jats:inline-formula><jats:alternatives><jats:tex-math>$$ {1.96}_{-0.17}^{+0.02} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mn>1.96</mml:mn> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.17</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.02</mml:mn> </mml:mrow> </mml:msubsup> </mml:math></jats:alternatives></jats:inline-formula> pb. Reasonable agreement with the differential cross-sections is found for most NLO models, while the NNLO calculations are generally in better agreement with the data. The differential cross-sections are interpreted using a Standard Model effective field-theory formalism and limits are set on Wilson coefficients of several four-fermion operators.</jats:p>

Item Type: Article
Uncontrolled Keywords: Hadron-Hadron Scattering, Jet Substructure and Boosted Jets, Top Physics
Divisions: Faculty of Science and Engineering > School of Physical Sciences
Depositing User: Symplectic Admin
Date Deposited: 15 May 2023 10:03
Last Modified: 16 Sep 2023 08:14
DOI: 10.1007/jhep04(2023)080
Open Access URL: https://arxiv.org/abs/2205.02817
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3170367