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Title: New observables for $CP$ violation in Higgs decays

Current experimental data on the 125 GeV Higgs boson still allow room for large $CP$ violation. The observables usually considered in this context are triple product asymmetries, which require an input of four visible particles after imposing momentum conservation. Here, we point out a new class of $CP$ -violating observables in Higgs physics which require only three reconstructed momenta. They may arise if the process involves an interference of amplitudes with different intermediate particles, which provide distinct “strong phases” in the form of the Breit-Wigner widths, in addition to possible “weak phases” that arise from $CP$ -violating couplings of the Higgs in the Lagrangian. As an example, we propose a forward-backward asymmetry of the charged lepton in the three-body Higgs decay, h → ℓ $-$+ γ , as a probe for $CP$ -violating Higgs couplings to Zγ and γγ pairs. In conclusion, we also discuss other processes exhibiting this type of $CP$ violation.
Authors:
 [1] ;  [2] ;  [3] ;  [2]
  1. California Inst. of Technology (CalTech), Pasadena, CA (United States). Lauritsen Lab. for High Energy Physics
  2. Centre National de la Recherche Scientifique (CNRS), Orsay (France). Lab. de Physique Theorique
  3. Argonne National Lab. (ANL), Argonne, IL (United States). High Energy Physics Division; Northwestern Univ., Evanston, IL (United States). Dept. of Physics and Astronomy
Publication Date:
OSTI Identifier:
1339095
Grant/Contract Number:
AC02-06CH11357; FG02-92-ER-40701; SC0010143; AC02- 06CH11357
Type:
Accepted Manuscript
Journal Name:
Physical Review. D, Particles, Fields, Gravitation and Cosmology
Additional Journal Information:
Journal Volume: 90; Journal Issue: 11; Journal ID: ISSN 1550-7998
Publisher:
American Physical Society (APS)
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25); National Science Foundation (NSF)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS