# Münster 2017 – wissenschaftliches Programm

## Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

# T: Fachverband Teilchenphysik

## T 6: QCD

### T 6.2: Vortrag

### Montag, 27. März 2017, 17:00–17:15, VSH 10

**Measurements of top-pair to ***Z***-boson cross section ratios at center-of-mass energies of ****√***s***=13,8,7**** TeV with the ATLAS detector and evaluation of measured cross sections constraints on PDFs and strong coupling constant.** — •Artur Trofymov — DESY, Hamburg, Germany

Ratios of top-quark pair to *Z*-boson production (*Z* → ℓ^{+} ℓ^{−} where ℓ = *e*, µ) cross
sections at center-of-mass energies of √*s* = 13, 8, 7 TeV are measured using data recorded by the ATLAS
experiment at the LHC. Data at √*s* = 13 TeV for both analyses are collected in 2015 with total integrated
luminosity of 3.2 fb^{−1}. Previously published *Z*-boson and top-quark pair cross sections measured at
√*s* = 8 and 7 TeV are corrected to phase space of measurements at √*s* = 13 TeV and used for
the ratios calculation. Single cross section ratios at a given √*s* for the two processes and same process at
different √*s*, as well as double ratios of two processes at different √*s*, are evaluated. The ratio results
are compared to the predictions calculated at next-to-next-to-leading order for different parton distribution functions
(PDFs). The correlated cross section measurements are used to obtain constraints on PDFs and the strong coupling
constant α_{s}.