Constraining anomalous $ZH$ couplings using $Z$ polarization parameters

Abstract

We study the anomalous ZZH vertex contributing to the Higgsstrahlung process at the LHC and future e+e− colliders using the polarization of the Z as a probe. We calculate the eight independent polarization parameters of the Z boson by using the spin density matrix formalism. We estimate 1σ limits on the anomalous ZZH couplings using the angular asymmetries of leptons from Z decay which are simply related to the eight polarization parameters. We discuss the results for a) two possible c.m.energies ( √ s =) 250 GeV and 500 GeV for the e+e− colliders, with the possibility of polarized e+e− beams, b) LHC at √ s = 14 TeV.