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Test of CP invariance in vector-boson fusion production of the Higgs boson in the H → ττ channel in proton–proton collisions at √s=13 TeV with the ATLAS detector

Research output: Contribution to Journal/MagazineJournal articlepeer-review

Article number135426
<mark>Journal publication date</mark>10/06/2020
<mark>Journal</mark>Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Number of pages25
Publication StatusPublished
<mark>Original language</mark>English


A test of CP invariance in Higgs boson production via vector-boson fusion is performed in the H → ττ decay channel. This test uses the Optimal Observable method and is carried out using 36.1fb-1 of √s=13 TeV proton–proton collision data collected by the ATLAS experiment at the LHC. Contributions from CP-violating interactions between the Higgs boson and electroweak gauge bosons are described by an effective field theory, in which the parameter d˜  governs the strength of CP violation. No sign of CP violation is observed in the distributions of the Optimal Observable, and d˜  is constrained to the interval [−0.090, 0.035] at the 68% confidence level (CL), compared to an expected interval of d˜ ∈ [-0.035,0.033] based upon the Standard Model prediction. No constraints can be set d˜ on at 95% CL, while an expected 95% CL interval of d˜ ∈ [-0.21,0.15] for the Standard Model hypothesis was expected.