Test of CP invariance in vectorboson fusion production of the Higgs boson in the $H\rightarrow\tau\tau$ channel in proton$$proton collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector
Abstract
A test of CP invariance in Higgs boson production via vectorboson fusion is performed in the $H\rightarrow\tau\tau$ decay channel. This test uses the Optimal Observable method and is carried out using 36.1 $\mathrm{fb}^{1}$ of $\sqrt{s}$ = 13 TeV proton$$proton collision data collected by the ATLAS experiment at the LHC. Contributions from CPviolating interactions between the Higgs boson and electroweak gauge bosons are described by an effective field theory, in which the parameter $\tilde{d}$ governs the strength of CP violation. No sign of CP violation is observed in the distributions of the Optimal Observable, and $\tilde{d}$ is constrained to the interval $[0.090, 0.035]$ at the 68% confidence level (CL), compared to an expected interval of $\tilde{d} \in [0.035,0.033]$ based upon the Standard Model prediction. No constraints can be set on $\tilde{d}$ at 95% CL, while an expected 95% CL interval of $\tilde{d} \in [0.21,0.15]$ for the Standard Model hypothesis was expected.
 Publication:

arXiv eprints
 Pub Date:
 February 2020
 arXiv:
 arXiv:2002.05315
 Bibcode:
 2020arXiv200205315A
 Keywords:

 High Energy Physics  Experiment
 EPrint:
 44 pages in total, author list starting page 28, 6 figures, 5 tables, published in Phys. Lett. B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HIGG201814