Measurement of $WW/WZ \to \ell \nu q q^{\prime}$ production with the hadronically decaying boson reconstructed as one or two jets in $pp$ collisions at $\sqrt{s}=8$ TeV with ATLAS, and constraints on anomalous gauge couplings

Abstract

CERN-LHC. This paper presents a study of the production of WW or WZ boson pairs, with one W boson decaying to electron-neutrino or muon-neutrino and one W or Z boson decaying hadronically. The analysis uses 20.2 fb-1 of sqrt(s)=8 TeV pp collision data, collected by the ATLAS detector at the Large Hadron Collider. Cross-sections for WW/WZ production are measured in high-pT 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 (WV->lvjj), and the case where it is reconstructed as a single jet (WV->lvJ). For the description of the WV->lvjj and WV->lvJ fiducial phase spaces, refer to section 8.1 and 8.2 of the paper. 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 (aTGCs). The aTGC search is done applying the same selection used for cross section measurement, plus an additional requirement for the jet-jet invariant mass (single jet mass) to be close to the W mass: 65 GeV < m_jj < 95 GeV (65 GeV < m_J < 95 GeV).