Abstract
This paper presents a study of the production of WW or WZ boson pairs, with one W boson decaying to enu or mu nu and one W or Z boson decaying hadronically. The analysis uses 20.2~text{ fb }^{-1} of sqrt{s} =8~text {TeV}pp collision data, collected by the ATLAS detector at the Large Hadron Collider. Cross-sections for WW / WZ production are measured in high-p_{mathrm {T}} fiducial regions defined close to the experimental event selection. The cross-section is measured for the case where the hadronically decaying boson is reconstructed as two resolved jets, and the case where it is reconstructed as a single jet. The transverse momentum distribution of the hadronically decaying boson is used to search for new physics. Observations are consistent with the Standard Model predictions, and 95% confidence intervals are calculated for parameters describing anomalous triple gauge-boson couplings.
Highlights
Background estimationThe methods for estimating the expected background yields and kinematic distributions are described
Systematic uncertainties in the V + jets shape are estimated by varying the Monte Carlo (MC) event generator used (Sherpa compared to Alpgen+Pythia)
Uncertainties in the signal shapes and in the Dfid parameter due to variations of the signal model are computed by varying the renormalization and factorization scales by factors of 2 and 0.5, and by comparing the nominal MC@next-to-leading order (NLO) signal samples to alternative samples generated with Sherpa and Powheg +Pythia 8
Summary
Measurements of W V → νqq production are performed using either two small-R jets or a single large-R jet to reconstruct the hadronically decaying V boson For both channels, the leptonically decaying W boson is reconstructed by requiring the presence of a lepton (electron or muon) and missing transverse momentum. The signal events peak near the W/Z mass in these distributions, while the shape of the dominant W + jets background is smoothly falling. In both channels, the signal is extracted from a fit to the dis-. An initial hardwarebased trigger stage is followed by two software-based triggers, which reduce the final event rate to about 400 Hz
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