Axion-Like Particles and the Higgs Decays h → PZ and h → Pl+l-

Axion-like particles (ALPs) are often defined as relatively light pseudoscalar particles and appear in many extensions of the Standard Model. Taking into account constraints on the free parameters from existing searches and explaining the g-2 deviation, we consider the contributions of ALPs with mass in the range of 1.5 GeV < m(a) < m(h) - m(z) to the exclusive Higgs decays h -> PZ and h -> Pl(+)l(-) with P being the pseudoscalar mesons pi(0), eta, eta', eta(c) and eta(b) in a model-independent approach. We find that, in most of the parameter space range, the contributions of ALP to these decay processes are very small, while in the case of the ALP mass m(a) approximately equaling the meson mass m(P), the contributions are significantly large.