1303.0365 (Alexander Yu. Korchin et al.)

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

Alexander Yu. Korchin, Vladimir A. Kovalchuk

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. 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 can be measured through the forward-backward asymmetry of fermions in the decay h -> gamma Z -> gamma f \bar{f}. Sizable values of this observable may testify violation of CPT symmetry. We suggest also a way 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 -> \bar{f} f. Deviation of measured value of \xi_1 from zero will indicate CP violation in the Higgs sector.

View original: http://arxiv.org/abs/1303.0365