Measurement of the charge asymmetry in highly boosted top-quark pair production in √s = 8 TeV pp collision data collected by the ATLAS experiment
In the pp → tt ̄ 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 produce...
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| Format: | Article |
| Status: | Published version |
| Publication date: | 2016 |
| Country: | Argentina |
| Institution: | UNLP |
| Repository: | SEDICI (UNLP) |
| Language: | English |
| OAI Identifier: | oai:sedici.unlp.edu.ar:10915/77618 |
| Online Access: | http://sedici.unlp.edu.ar/handle/10915/77618 |
| Access Level: | Open access |
| Keyword: | Ciencias Exactas Física charge asymmetry highly boosted top-quark pair production pp collision data |
| Summary: | In the pp → tt ̄ 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 √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 (mtt ̄ > 0.75 TeV) and an absolute rapidity difference of the top and anti-top quark candidates within −2 < |yt| − |yt ̄| < 2 is measured to be 4.2 ± 3.2%, in agreement with the Standard Model prediction at next-to-leading order. A differential measurement in three tt ̄ mass bins is also presented. |
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