Differential tt¯ cross-section measurements using boosted top quarks in the all-hadronic final state with 139 fb−1 of ATLAS data

Academic article

Year of publication: 2023
Journal: Journal of High Energy Physics (JHEP)
External websites: Cristin; Arkiv; Doi
Contributors: G. Aad, B. Abbott, D.C. Abbott, Abud Abed Abud, S.H. Abidi, A. Aboulhorma, H. Abramowicz, H. Abreu, Y. Abulaiti, Hoffman Abusleme Hoffman, B.S. Acharya, B. Achkar, L. Adam, Bourdarios Adam Bourdarios, L. Adamczyk, L. Adamek, S.V. Addepalli, J. Adelman, A. Adiguzel, S. Adorni, T. Adye, A.A. Affolder, Y. Afik, C. Agapopoulou, M.N. Agaras, J. Agarwala, A. Aggarwal, C. Agheorghiesei, J.A. Aguilar-Saavedra, A. Ahmad, F. Ahmadov, W.S. Ahmed, X. Ai, G. Aielli, I. Aizenberg, S. Akatsuka, M. Akbiyik, T.P.A. Åkesson, Khoury Al Khoury, G.L. Alberghi, J. Albert, P. Albicocco, Verzini Alconada Verzini, S. Alderweireldt, M. Aleksa, C. Alexa, T. Alexopoulos, A. Alfonsi, F. Alfonsi, M. Alhroob, B. Ali, S. Ali, G. Alimonti, C. Allaire, B.M.M. Allbrooke, P.P. Allport, A. Aloisio, F. Alonso, C. Alpigiani, Camelia Alunno Camelia, Estevez Alvarez Estevez, M.G. Alviggi, Coutinho Amaral Coutinho, A. Ambler, L. Ambroz, C. Amelung, D. Amidei, Dos Amor Dos Santos, S. Amoroso, K.R. Amos, C.S. Amrouche, Viktor Ananiev, C. Anastopoulos, N. Andari, T. Andeen, J.K. Anders, S.Y. Andrean, A. Andreazza, S. Angelidakis, A. Angerami, A. Annovi, C. Antel, M.T. Anthony, E. Antipov, M. Antonelli, D.J.A. Antrim, F. Anulli, M. Aoki, M.A. Aparo, Bella Aperio Bella, N. Aranzabal, Ferraz Araujo Ferraz, C. Arcangeletti, A.T.H. Arce, E. Arena, J.-F. Arguin, S. Argyropoulos, J.-H. Arling, A.J. Armbruster, A. Armstrong

Summary

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 (pT) greater than 500 GeV. The observed data are unfolded to remove detector effects. The particle-level cross-section, multiplied by the tt¯→WWbb¯¯ branching fraction and measured in a fiducial phase space defined by requiring the leading and second-leading jets to have pT > 500 GeV and pT > 350 GeV, respectively, is 331 ± 3(stat.) ± 39(syst.) fb. This is approximately 20% lower than the prediction of 398+48−49 fb by Powheg+Pythia 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 1.94 ± 0.02(stat.) ± 0.25(syst.) pb. This agrees with the NNLO prediction of 1.96+0.02−0.17 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.