Search for heavy resonances decaying into a $W$ or $Z$ boson and a Higgs boson in final states with leptons and $b$-jets in 36 fb${}^{-1}$ of $\sqrt{s}=13$ TeV $pp$ collisions with the ATLAS detector

Abstract

A search is conducted for new resonances decaying into a $W$ or $Z$ boson and a 125 GeV Higgs boson in the $\nu \bar{\nu }b\bar{b}$, ${\ell }^{\pm }\nu b\bar{b}$, and ${\ell }^{+}{\ell }^{-}b\bar{b}$ final states, where ${\ell }^{\pm }=e^{\pm }$ or ${\mu }^{\pm }$, in $pp$ collisions at $\sqrt{s}=13$ TeV. The data used correspond to a total integrated luminosity of 36.1 fb${}^{-1}$ collected with the ATLAS detector at the Large Hadron Collider during the 2015 and 2016 data-taking periods. The search is conducted by examining the reconstructed invariant or transverse mass distributions of $Wh$ and $Zh$ candidates for evidence of a localised excess in the mass range of 220 GeV up to 5 TeV. No significant excess is observed and the results are interpreted in terms of constraints on the production cross-section times branching fraction of heavy $W^{\prime }$ and $Z^{\prime }$ resonances in heavy-vector-triplet models and the CP-odd scalar boson $A$ in two-Higgs-doublet models. Upper limits are placed at the 95% confidence level and range between $9.0\times 10^{-4}$ pb and $8.1\times 10^{-1}$ pb depending on the model and mass of the resonance.

52 pages in total, author list starting page 36, 8 figures, 5 tables, published version including Erratum corrections available at https://link.springer.com/article/10.1007%2FJHEP11%282018%29051. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/EXOT-2016-10