Measurement of the energy asymmetry in tt¯ j production at 13 TeV with the ATLAS experiment and interpretation in the SMEFT framework
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Archivos
Fecha
2022-04
Profesor/a Guía
Facultad/escuela
Idioma
en
Título de la revista
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Título del volumen
Editor
Institute for Ionics
Nombre de Curso
Licencia CC
ATRIBUCIÓN 4.0 INTERNACIONAL
CC BY 4.0
Deed
Licencia CC
https://creativecommons.org/licenses/by/4.0/deed.es
Resumen
A measurement of the energy asymmetry in jet-associated top-quark pair production is presented using 139fb-1 of data collected by the ATLAS detector at the Large Hadron Collider during pp collisions at s=13TeV. The observable measures the different probability of top and antitop quarks to have the higher energy as a function of the jet scattering angle with respect to the beam axis. The energy asymmetry is measured in the semileptonic tt¯ decay channel, and the hadronically decaying top quark must have transverse momentum above 350GeV. The results are corrected for detector effects to particle level in three bins of the scattering angle of the associated jet. The measurement agrees with the SM prediction at next-to-leading-order accuracy in quantum chromodynamics in all three bins. In the bin with the largest expected asymmetry, where the jet is emitted perpendicular to the beam, the energy asymmetry is measured to be - 0.043 ± 0.020 , in agreement with the SM prediction of - 0.037 ± 0.003. Interpreting this result in the framework of the Standard Model effective field theory (SMEFT), it is shown that the energy asymmetry is sensitive to the top-quark chirality in four-quark operators and is therefore a valuable new observable in global SMEFT fits. © 2022, The Author(s).
Notas
Indexación: Scopus.
Palabras clave
Hadron, Lepton, Standard Model
Citación
European Physical Journal C, Volume 82, Issue 4, April 2022, Article number 374
DOI
10.1140/epjc/s10052-022-10101-w