Test of CP invariance in vector-boson fusion production of the Higgs boson using the Optimal Observable method in the ditau decay channel with the ATLAS detector
Abstract
A test of CP invariance in Higgs boson production via vector-boson fusion using the method of the Optimal Observable is presented. The analysis exploits the decay mode of the Higgs boson into a pair of τ leptons and is based on 20.3 fb^{-1} of proton-proton collision data at √{s} = 8 TeV collected by the ATLAS experiment at the LHC. Contributions from CP-violating interactions between the Higgs boson and electroweak gauge bosons are described in an effective field theory framework, in which the strength of CP violation is governed by a single parameter tilde{d}. The mean values and distributions of CP-odd observables agree with the expectation in the Standard Model and show no sign of CP violation. The CP-mixing parameter tilde{d} is constrained to the interval (-0.11,0.05) at 68% confidence level, consistent with the Standard Model expectation of tilde{d}=0.
- Publication:
-
European Physical Journal C
- Pub Date:
- December 2016
- DOI:
- 10.1140/epjc/s10052-016-4499-5
- arXiv:
- arXiv:1602.04516
- Bibcode:
- 2016EPJC...76..658A
- Keywords:
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- High Energy Physics - Experiment
- E-Print:
- 23 pages plus author list (40 pages total), 8 figures, 2 tables, published version, all figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HIGG-2015-06