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CERN Accelerating science

ATLAS Note
Report number ATL-PHYS-PROC-2016-117
Title Measurement of ttZ and ttW production at ATLAS in 13 TeV data, using trilepton and same charge dimuon final states
Author(s) Bessidskaia Bylund, Olga (Stockholm U.) (+)
Corporate Author(s) The ATLAS collaboration
Collaboration ATLAS Collaboration
Publication 2016
Imprint 29 Aug 2016
Number of pages 4
In: PoS LHCP2016 (2016) 237
In: 4th Conference on Large Hadron Collider Physics 2016 (LHCP 2016), Lund, Sweden, 13 - 18 Jun 2016, pp.237
DOI 10.22323/1.276.0237
Subject category Particle Physics - Experiment
Accelerator/Facility, Experiment CERN LHC ; ATLAS
Free keywords TOP ; EWEAK
Abstract The production of $t \bar t Z$ serves as an important probe of the coupling of top quarks to Z bosons. Modifications to the $t \bar t Z$ vertex by physics beyond the Standard Model would have an effect on the $t \bar t Z$ production rates. The first measurements of $t \bar t Z$ production were performed in 8 TeV data by the ATLAS and CMS experiments at the LHC. At 13 TeV collision energy, the production rate of $t \bar t Z$ increases by almost a factor of 4 and the effects of new physics, if present, should become more prominent. The first measurement by ATLAS of $t \bar t Z$ production at 13 TeV is presented here, with focus on the selection region that requires three charged leptons. This signature constitutes a compromise between a higher branching ratio for hadronic top decay chains and the better separation from background of the leptonic top decays. Moreover, the $t \bar t W$ process is measured, using final states that contain either three charged leptons or two muons of the same charge. The first observation of $t \bar t W$ was performed by ATLAS using 8 TeV data. Measuring this process can probe several different models for physics beyond the Standard Model.
Copyright/License Preprint: (License: CC-BY-4.0)

Corresponding record in: Inspire


 Записът е създаден на 2016-08-29, последна промяна на 2018-09-24