Aachen 2019 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 83: Top-Physik III
T 83.6: Vortrag
Donnerstag, 28. März 2019, 17:15–17:30, S10
Studies on ttbar charge asymmetry in the photon handle with ATLAS experiment — •Amartya Rej and Ivor Fleck — Universität Siegen, Germany
Tevatron measurements show a 2.2σ deviation from the Standard Model(SM) inclusive tt forward-backward asymmetry(AFB), whereas measurements of the tt charge asymmetry(AC) at the LHC exhibit a good consistency with the SM expectations. It is speculated to have an excess at the Tevatron and no excess at the LHC if there is a cancellation of some type. The addition of a final state photon in the top pair production changes this: it can increase the fraction of events from quark annihilation, which increases the asymmetry. For example, AC(ttγ) at √s = 14 TeV can be found to be −0.035±0.010 at LO calculation. To measure it, tt production in association with a photon coming from the production processes is studied with the ATLAS detector at √s = 13 TeV with the full Run2 dataset. In the presentation, the MC production, top reconstruction and the analysis strategy will be discussed.