# Measurement of the charge asymmetry in highly boosted top-quark pair production in $\sqrt{s} =$ 8 TeV $pp$ collision data collected by the ATLAS experiment

Abstract : In the $pp \rightarrow t\bar{t}$ process the angular distributions of top and anti-top quarks are expected to present a subtle difference, which could be enhanced by processes not included in the Standard Model. This Letter presents a measurement of the charge asymmetry in events where the top-quark pair is produced with a large invariant mass. The analysis is performed on 20.3 fb$^{-1}$ of $pp$ collision data at $\sqrt{s} =$ 8 TeV collected by the ATLAS experiment at the LHC, using reconstruction techniques specifically designed for the decay topology of highly boosted top quarks. The charge asymmetry in a fiducial region with large invariant mass of the top-quark pair ($m_{t\bar{t}} >$ 0.75 TeV) and an absolute rapidity difference of the top and anti-top quark candidates within $-$2 $< |y_t| - |y_{\bar{t}}| <$ 2 is measured to be 4.2 $\pm$ 3.2%, in agreement with the Standard Model prediction at next-to-leading order. A differential measurement in three $t\bar{t}$ mass bins is also presented.
Document type :
Journal articles

http://hal.in2p3.fr/in2p3-01247039
Contributor : Emmanuelle Vernay <>
Submitted on : Monday, December 21, 2015 - 8:37:27 AM
Last modification on : Thursday, August 6, 2020 - 3:09:25 AM

### Citation

G. Aad, S. Albrand, S. Berlendis, C. Camincher, J. Collot, et al.. Measurement of the charge asymmetry in highly boosted top-quark pair production in $\sqrt{s} =$ 8 TeV $pp$ collision data collected by the ATLAS experiment. Physics Letters B, Elsevier, 2016, 756, pp.52-71. ⟨10.1016/j.physletb.2016.02.055⟩. ⟨in2p3-01247039⟩

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