Next-to-leading-order corrections to the Higgs strahlung process from electron\u2013positron collisions in extended Higgs models

Abstract

We present the cross section for e^{+}e^{-}rightarrow hZ with arbitrary sets of electron and Z boson polarizations at the full next-to-leading order in various extended Higgs models, such as the Higgs singlet model (HSM), the inert doublet model (IDM) and the two Higgs doublet model (2HDM). We systematically perform complete one-loop calculations to the helicity amplitudes in the on-shell renormalization scheme, and present the full analytic results as well as numerical evaluations. The deviation Delta R^{hZ} in the total cross section from its standard model (SM) prediction is comprehensively analyzed, and the differences among these models are discussed in details. We find that new physics effects appearing in the renormalized hZZ vertex almost govern the behavior of Delta R^{hZ}, and it takes a negative value in most cases. The possible size of Delta R^{hZ} reaches several percent under the theoretical and experimental bounds. We also analyze the deviation Delta R^{hZ}_{XY} in the total cross section times decay branching ratios of the discovered Higgs boson by utilizing the H-COUP program. It is found that the four types of 2HDMs can be discriminated by analyzing the correlation between Delta R^{hZ}_{tau tau } and Delta R^{hZ}_{bb} and those between Delta R^{hZ}_{tau tau } and Delta R^{hZ}_{cc}. Furthermore, the HSM and the IDM can be discriminated from the 2HDMs by measuring Delta R^{hZ}_{WW}. These signatures can be tested by precision measurements at future Higgs factories such as the International Linear Collider.