Measurements of inclusive and differential fiducial cross-sections of tt¯γ production in leptonic final states at s√=13 TeV in ATLAS

Research output: Contribution to journalArticle

  • External authors:
  • Agni Bethani
  • Alexander Bitadze
  • Jonathan Crane
  • Cinzia Da Via
  • Nicholas Dann
  • Sam Dysch
  • Alessandra Forti
  • Emily Hanson
  • James Howarth
  • David Lack
  • Ivan Lopez Paz
  • Jiri Masik
  • Stephen Menary
  • Alexander Oh
  • Joleen Pater
  • Yvonne Peters
  • Rebecca Pickles
  • Yang Qin
  • Jacob Rawling
  • Nicolas Scharmberg
  • Savanna Shaw
  • Terence Wyatt

Abstract

Inclusive and differential cross-sections for the production of a top-quark pair in association with a photon are measured with proton-proton collision data corresponding to an integrated luminosity of 36.1 fb −1 , collected by the ATLAS detector at the LHC in 2015 and 2016 at a centre-of-mass energy of 13 TeV . The measurements are performed in single-lepton and dilepton final states in a fiducial volume. Events with exactly one photon, one or two leptons, a channel-dependent minimum number of jets, and at least one b-jet are selected. Neural network algorithms are used to separate the signal from the backgrounds. The fiducial cross-sections are measured to be 521±9(stat.)±41(sys.) fb and 69±3(stat.)±4(sys.) fb for the single-lepton and dilepton channels, respectively. The differential cross-sections are measured as a function of photon transverse momentum, photon absolute pseudorapidity, and angular distance between the photon and its closest lepton in both channels, as well as azimuthal opening angle and absolute pseudorapidity difference between the two leptons in the dilepton channel. All measurements are in agreement with the theoretical predictions.

Bibliographical metadata

Original languageEnglish
JournalThe Journal of High Energy Physics
Early online date3 May 2019
DOIs
Publication statusPublished - 2019