Rare Z-decay into light CP-odd Higgs bosons: a comparative study in different new physics models

Abstract

Various new physics models predict a light CP-odd Higgs boson (labeled as $a$) and open up new decay modes for Z-boson, such as $Z\to \bar{f}fa$, $Z\to a\gamma$ and $Z\to aaa$, which could be explored at the GigaZ option of the ILC. In this work we investigate these rare decays in several new physics models, namely the type-II two Higgs doublet model (type-II 2HDM), the lepton-specific two Higgs doublet model (L2HDM), the nearly minimal supersymetric standard model (nMSSM) and the next-to-minimal supersymmetric standard model (NMSSM). We find that in the parameter space allowed by current experiments, the branching ratios can reach $10^{-4}$ for $Z\to \bar{f}fa$ ($f=b,\tau$), $10^{-9}$ for $Z\to a\gamma$ and $10^{-3}$ for $Z\to aaa$, which implies that the decays $Z\to \bar{f}fa$ and $Z\to aaa$ may be accessible at the GigaZ option. Moreover, since different models predict different patterns of the branching ratios, the measurement of these rare decays at the GigaZ may be utilized to distinguish the models.

Version in JHEP (discussions added, errors corrected)

References in corpus (21)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Likelihoods and Parameters from the WMAP data
• micrOMEGAs2.0: a program to calculate the relic density of dark matter in a generic model
• Models of Yukawa interaction in the two Higgs doublet model, and their collider phenomenology
• Higgs Sector in Extensions of the MSSM
• The NMSSM Close to the R-symmetry Limit and Naturalness in $h\to aa$ Decays for $m_a<2\mb$
• Lepton-Specific Two-Higgs Doublet Model: Experimental Constraints and Implication on Higgs Phenomenology
• New constraints on a light CP-odd Higgs boson and related NMSSM Ideal Higgs Scenarios
• The LHC Discovery Potential of a Leptophilic Higgs
• The Leptonic Higgs as a Messenger of Dark Matter
• Charged Higgs phenomenology in the lepton-specific two Higgs doublet model
• Phenomenology of the nMSSM from colliders to cosmology
• Has HyperCP Observed a Light Higgs Boson?
• Radiative Upsilon decays and a light pseudoscalar Higgs in the NMSSM
• LHC discovery potential of the lightest NMSSM Higgs in the h1 -> a1 a1 -> 4 muons channel
• Many Light Higgs Bosons in the NMSSM
• B meson Dileptonic Decays in NMSSM with a Light CP-odd Higgs Boson
• A light CP-odd Higgs boson and the muon anomalous magnetic moment
• Experimental constraints on nMSSM and implications on its phenomenology
• Constraints of dark matter direct detection experiments on the MSSM and implications for LHC Higgs searches
• Lightest Neutralino Mass in the MNSSM
• The light pseudoscalar Higgs boson in NMSSM