Constraints on Higgs boson properties using $WW^{*}(\rightarrow e\nu\mu\nu)\;jj$ production in $36.1 \mathrm{fb}^{-1}$ of $\sqrt{s}=13 TeV$ pp collisions with the ATLAS detector

This note presents the results of two studies of Higgs boson properties using the $WW^*(\rightarrow e\nu\mu\nu)jj$ final state, based on a dataset corresponding to $36.1\,\mathrm{fb}^{-1}$ of $\sqrt{s}=13\,\mathrm{TeV}$ proton-proton collisions recorded by the ATLAS experiment at the Large Hadron Collider. The first study targets Higgs boson production via gluon fusion and constrains the CP properties of the effective Higgs-gluon vertex for the first time in the $e\nu\mu\nu jj$ final state. Using both angular distributions and the overall rate, the ratio of the CP-odd to CP-even coupling strength scale factors of the effective Higgs-gluon vertex is constrained to $\kappa_{Agg}/\kappa_{Hgg} = 0.0 \pm 0.4 (\mathrm{stat.}) \pm 0.3 (\mathrm{syst.})$. The second study investigates vector boson fusion to individually access the Higgs boson couplings to longitudinally and transversely polarised $W$ and $Z$ bosons in both the production and the decay of the Higgs boson; these polarisations have not been previously constrained in this process. The polarisation coupling-strength scale factors, defined as the ratios of the measured polarisation-dependent coupling strengths to those predicted by the Standard Model, are constrained using shape and rate information to the values $a_\mathrm{L}=0.91^{+0.10}_{-0.18}$(stat.)$^{+0.09}_{-0.18}$(syst.) and $a_{\mathrm{T}}=1.16 \pm 0.4 $(stat.)$ ^{+0.4}_{-0.3} $(syst.). These coupling strengths are translated into pseudo-observables, resulting in $\kappa_{VV}=0.90^{+0.10}_{-0.18}$(stat.)$^{+0.09}_{-0.16}$(syst.) and $\epsilon_{VV} =0.13^{+0.28}_{-0.20}$ (stat.)$^{+0.08}_{-0.10}$(syst.). All results are consistent with the SM predictions.