Measurement of the cross-section of high transverse momentum vector bosons reconstructed as single jets and studies of jet substructure in $pp$ collisions at ${\sqrt{s}}$ = 7 TeV with the ATLAS detector

Abstract: This paper presents a measurement of the cross-section for high transverse momentum $W$ and $Z$ bosons produced in $pp$ collisions and decaying to all-hadronic final states. The data used in the analysis were recorded by the ATLAS detector at the CERN Large Hadron Collider at a centre-of-mass energy of $\sqrt{s}=7~\rm TeV$ and correspond to an integrated luminosity of $4.6~\rm fb^{-1}$. The measurement is performed by reconstructing the boosted $W$ or $Z$ bosons in single jets. The reconstructed jet mass is used to identify the $W$ and $Z$ bosons, and a jet substructure method based on energy cluster information in the jet centre-of-mass frame is used to suppress the large multi-jet background. The cross-section for events with a hadronically decaying $W$ or $Z$ boson, with transverse momentum $p_{\rm T}>320\,{\rm GeV}$ and pseudorapidity $|\eta|<1.9$, is measured to be $\sigma_{W+Z}= 8.5 \pm 1.7$ pb and is compared to the next-to-leading-order calculations. The selected events are further used to study jet grooming techniques.