Decay of the Higgs boson $h\to\tau^- \tau^+\to\pi^-\nu_{\tau}\,\pi^+{\bar \nu}_\tau$ for a non-Hermitian Yukawa interaction

Abstract

The differential rate of the decay of the Higgs boson ($h$) to a pair of $\tau $ leptons with their subsequent decay in the $\tau^-\to \pi^- \nu_\tau$ and $\tau^+\to \pi^+{\bar \nu}_\tau$ channels is studied. The Yukawa interaction between the Higgs boson and the $\tau$ leptons is assumed to include scalar ($S$) and pseudoscalar ($PS$) couplings. Angular distributions of the pions in the $h\to\tau^- \tau^+\to\pi^-\nu_{\tau}\,\pi^+{\bar \nu}_\tau$ decay are considered. For real values of the $S$ and $PS$ couplings, this decay is known to be a source of information on $\mathcal{CP}$ violation in the $h \tau \tau $ interaction. In the present paper, the main attention is paid to a possible non-Hermiticity of this interaction. Influence of non-Hermiticity on the distribution of the angle between planes of the $ \tau^- \to \pi^-\nu_{\tau}$ and $\tau^+ \to \pi^+ {\bar \nu}_{\tau}$ decays, and distribution of the polar angle of one of the pions are analyzed. Asymmetries sensitive to parameters of $\mathcal{CP}$ violation and non-Hermiticity of $h \tau \tau$ interaction are proposed.