Polarization effects in the Higgs boson decay to gamma Z and test of CP and CPT symmetries

Abstract

Polarization characteristics of gamma gamma and gamma Z states in the Higgs boson decays h -> gamma gamma and h -> gamma Z are discussed. Based on effective Lagrangian, describing h gamma gamma and h gamma Z interactions with CP-even and CP-odd parts, we calculate polarization parameters xi_1, xi_2, xi_3. A nonzero value of the photon circular polarization, defined by parameter xi_2, arises due to presence of both parts in effective Lagrangian and its non-Hermiticity. The circular polarization is proportional to the forward-backward asymmetry of fermions in the decay h -> gamma Z -> gamma f bar{f}. Measurement of this observable would allow one to search for deviation from the standard model and possible violation of CPT symmetry. We discuss also a possibility to measure parameters xi_1, xi_3, describing correlation of linear polarizations of photon and Z boson, in the decay h -> gamma* Z -> l+ l- Z via distribution over the azimuthal angle between the decay planes of gamma* -> l+ l- and Z -> f bar{f}. Deviation of the measured value of xi_1 from zero will indicate CP violation in the Higgs sector.

9 pages, revtex4; v2: list of references is extended and updated, estimates of observability at the LHC of proposed processes are added, accepted for publication in Phys. Rev. D; v3: minor changes to adjust with the journal version

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• Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC
• Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC
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• CP Violation in Higgs Diphoton Decay in Models with Vectorlike Heavy Fermions
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Cited by in corpus (22)

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• New Observables for CP Violation in Higgs Decays
• Enhanced $thj$ signal at the LHC with $h\to \gamma \gamma$ decay and $\mathcal{C}\mathcal{P}$-violating top-Higgs coupling
• A note on Higgs decays into $Z$ boson and $J/\Psi ({\rm Y})$
• Angular distribution and forward-backward asymmetry of the Higgs-boson decay to photon and lepton pair
• Probing CP violation in $h\to {\tau }^{-}{\tau }^{+}$ at the LHC
• Rare and exclusive few-body decays of the Higgs, Z, W bosons, and the top quark
• Probing anomalous Higgs couplings in $H\to ZV$ decays
• Decay of the Higgs boson to ${\tau }^{-}{\tau }^{+}$ and non-Hermiticity of the Yukawa interaction
• Probing CP-violating $h\bar{t}t$ coupling in $e^{+}{e}^{-}\to h\gamma$
• CP-odd component of the lightest neutral Higgs boson in the MSSM
• Higgs decays to $\gamma$ and invisible particles in the standard model
• Probing CP Violation in $h\to Z\gamma$ with Background Interference
• A Boost to $h\to Z\gamma$: from LHC to Future $e^{+}{e}^{-}$ Colliders
• The SM expected branching ratio for $h\to \gamma \gamma$ and an excess for $h\to Z\gamma$
• Theory of Dirac Dark Matter: Higgs Decays and EDMs
• Decays of a neutral particle with zero spin and arbitrary CP parity into two off-mass-shell Z bosons
• CP violation from spin-1 resonances in a left-right dynamical Higgs context
• Measuring $CP$ nature of $h\tau \bar{\tau }$ coupling at $e^{-}p$ collider
• Energy correlation of bottom quarks from decays of top quarks in electron$-$positron annihilation
• Exclusive rare Higgs decays into lepton pair and light mesons
• Higgs boson decay to lepton pair and photon and possible non-Hermiticity of the Yukawa interaction