Measurements of b-jet tagging efficiency with the ATLAS detector using tt¯ events at √s=13 TeV

Summary, in English

The efficiency to identify jets containing b-hadrons (b-jets) is measured using a high purity sample of dileptonic top quark-antiquark pairs (tt¯) selected from the 36.1 fb−1 of data collected by the ATLAS detector in 2015 and 2016 from proton-proton collisions produced by the Large Hadron Collider at a centre-of-mass energy s=13 TeV. Two methods are used to extract the efficiency from tt¯ events, a combinatorial likelihood approach and a tag-and-probe method. A boosted decision tree, not using b-tagging information, is used to select events in which two b-jets are present, which reduces the dominant uncertainty in the modelling of the flavour of the jets. The efficiency is extracted for jets in a transverse momentum range from 20 to 300 GeV, with data-to-simulation scale factors calculated by comparing the efficiency measured using collision data to that predicted by the simulation. The two methods give compatible results, and achieve a similar level of precision, measuring data-to-simulation scale factors close to unity with uncertainties ranging from 2% to 12% depending on the jet transverse momentum. © 2018, The Author(s).

• Author: M Aaboud; Torsten Åkesson; Simona Bocchetta; Eric Corrigan; Caterina Doglioni; Eva Brottmann Hansen; Vincent Hedberg; Göran Jarlskog; Charles Kalderon; Edgar Kellermann; Balazs Konya; Else Lytken; Katja Mankinen; Ulf Mjörnmark; Ruth Pöttgen; Trine Poulsen; Oxana Smirnova; Oleksandr Viazlo; L. Zwalinski
• Department/s: Particle and nuclear physics; eSSENCE: The e-Science Collaboration
• Publishing year: 2018
• Language: English
• Publication/Series: Journal of High Energy Physics
• Volume: 2018
• Issue: 8
• Links: http://dx.doi.org/10.1007/JHEP08(2018)089
• Document type: Journal article
• Publisher: Springer
• Topic: Subatomic Physics
• Keywords: Hadron-Hadron scattering (experiments)
• Status: Published
• ISBN/ISSN/Other: ISSN: 1029-8479