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Oxana Smirnova

Oxana Smirnova

Senior Lecturer, Deputy Head of division

Oxana Smirnova

Measurement of the jet mass in high transverse momentum Z(→bb‾)γ production at s=13TeV using the ATLAS detector

Author

  • G. Aad
  • T.P.A. Åkesson
  • S.S. Bocchetta
  • L. Bryngemark
  • E.E. Corrigan
  • C. Doglioni
  • K. Gregersen
  • E. Hansen
  • V. Hedberg
  • G. Jarlskog
  • C.W. Kalderon
  • E. Kellermann
  • B. Konya
  • E. Lytken
  • K.H. Mankinen
  • C. Marcon
  • J.U. Mjörnmark
  • G.A. Mullier
  • R. Poettgen
  • T. Poulsen
  • E. Skorda
  • O. Smirnova
  • L. Zwalinski

Summary, in English

The integrated fiducial cross-section and unfolded differential jet mass spectrum of high transverse momentum Z→bb‾ decays are measured in Zγ events in proton–proton collisions at s=13TeV. The data analysed were collected between 2015 and 2016 with the ATLAS detector at the Large Hadron Collider and correspond to an integrated luminosity of 36.1fb−1. Photons are required to have a transverse momentum pT>175GeV. The Z→bb‾ decay is reconstructed using a jet with pT>200GeV, found with the anti-kt R=1.0 jet algorithm, and groomed to remove soft and wide-angle radiation and to mitigate contributions from the underlying event and additional proton–proton collisions. Two different but related measurements are performed using two jet grooming definitions for reconstructing the Z→bb‾ decay: trimming and soft drop. These algorithms differ in their experimental and phenomenological implications regarding jet mass reconstruction and theoretical precision. To identify Z bosons, b-tagged R=0.2 track-jets matched to the groomed large-R calorimeter jet are used as a proxy for the b-quarks. The signal yield is determined from fits of the data-driven background templates to the different jet mass distributions for the two grooming methods. Integrated fiducial cross-sections and unfolded jet mass spectra for each grooming method are compared with leading-order theoretical predictions. The results are found to be in good agreement with Standard Model expectations within the current statistical and systematic uncertainties. © 2020 The Author

Department/s

  • Particle and nuclear physics
  • eSSENCE: The e-Science Collaboration

Publishing year

2021

Language

English

Publication/Series

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

Volume

812

Document type

Journal article

Publisher

Elsevier

Topic

  • Subatomic Physics

Status

Published

ISBN/ISSN/Other

  • ISSN: 0370-2693