Measurement of the charge asymmetry in highly boosted top-quark pair production in root s=8 TeV pp collision data collected by the ATLAS experiment
Number of Authors: 2853
2016 (English)In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 756, 52-71 p.Article in journal (Refereed) Published
In the pp -> t (t) over bar 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 root 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 (t) over bar) > 0.75 TeV) and an absolute rapidity difference of the top and anti-top quark candidates within -2 vertical bar y(t)vertical bar - vertical bar y(<(t) over bar)vertical bar < 2is measured to be 4.2 +/- 3.2%, in agreement with the Standard Model prediction at next-to-leading order. A differential measurement in three <(t)over bar> mass bins is also presented.
Place, publisher, year, edition, pages
2016. Vol. 756, 52-71 p.
IdentifiersURN: urn:nbn:se:su:diva-130661DOI: 10.1016/j.physletb.2016.02.055ISI: 000373569200008OAI: oai:DiVA.org:su-130661DiVA: diva2:932280