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 1

$\sigma$ 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

$(\sqrt{s}=)$ 250 GeV and 500 GeV for the

$e^+e^-$ colliders, with the possibility of polarized

$e^+e^-$ beams, b) LHC at

$\sqrt{s}=14\text{ TeV}$ .