## Measurements of top-quark pair to \(Z\)-boson cross-section ratios at \(\sqrt{s}\) \(=13 , 8, 7\) TeV with the ATLAS detector

Please always quote using this URN: urn:nbn:de:bvb:20-opus-173544

- Ratios of top-quark pair to \(Z\)-boson cross sections measured from proton-proton collisions at the LHC centre-of-mass energies of \(\sqrt{s}\) = 13 TeV, 8 TeV, and 7 TeV are presented by the ATLAS Collaboration. Single ratios, at a given \(\sqrt{s}\) for the two processes and at different \(\sqrt{s}\) for each process, as well as double ratios of the two processes at different \(\sqrt{s}\), are evaluated. The ratios are constructed using previously published ATLAS measurements of the \({t\overline{t}}\) and \(Z\)-boson production crossRatios of top-quark pair to \(Z\)-boson cross sections measured from proton-proton collisions at the LHC centre-of-mass energies of \(\sqrt{s}\) = 13 TeV, 8 TeV, and 7 TeV are presented by the ATLAS Collaboration. Single ratios, at a given \(\sqrt{s}\) for the two processes and at different \(\sqrt{s}\) for each process, as well as double ratios of the two processes at different \(\sqrt{s}\), are evaluated. The ratios are constructed using previously published ATLAS measurements of the \({t\overline{t}}\) and \(Z\)-boson production cross sections, corrected to a common phase space where required, and a new analysis of \(Z\) → ℓ\(^+\)ℓ\(^-\) where ℓ = \(e, µ\) at \(\sqrt{s}\) = 13 TeV performed with data collected in 2015 with an integrated luminosity of 3.2 fb\(^−1\). Correlations of systematic uncertainties are taken into account when evaluating the uncertainties in the ratios. The correlation model is also used to evaluate the combined cross section of the \(Z\) → \(e\)\(^+\)\(e\)\(^−\) and the \(Z\) → \(µ\)\(^+\)\(µ\)\(^−\) channels for each \(\sqrt{s}\) value. The results are compared to calculations performed at next-to-next-to-leading-order accuracy using recent sets of parton distribution functions. The data demonstrate significant power to constrain the gluon distribution function for the Bjorken-\(x\) values near 0.1 and the light-quark sea for \(x\) < 0.02.…

URN: | urn:nbn:de:bvb:20-opus-173544 |
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Document Type: | Journal article |

Faculties: | Fakultät für Physik und Astronomie |

Language: | English |

Parent Title (English): | Journal of High Energy Physics |

Year of Completion: | 2017 |

Volume: | 2017 |

Issue: | 02 |

Article Number: | 117 |

Source: | Journal of High Energy Physics (2017) 02:117. https://doi.org/10.1007/JHEP02(2017)117 |

DOI: | https://doi.org/10.1007/JHEP02(2017)117 |

Dewey Decimal Classification: | 5 Naturwissenschaften und Mathematik / 53 Physik / 539 Moderne Physik |

Tag: | Hadron-Hadron scattering (experiments); High energy physics |

Release Date: | 2022/03/31 |

Creating Corporation: | The ATLAS Collaboration |

OpenAIRE: | OpenAIRE |

Licence (German): | CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International |