Charged lepton distributions as a probe of contacte+e−HZinteractions at a linear collider with polarized beams

Abstract

We examine very general four-point interactions arising from new physics and contributing to the Higgs production process ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}HZ$. We write all possible forms for these interactions consistent with Lorentz invariance. We allow the possibility of $CP$ violation. Contributions to the process from anomalous $ZZH$ and $\ensuremath{\gamma}ZH$ interactions studied earlier arise as a special case of our four-point amplitude. We consider the decay of $Z$ into a charged-lepton pair and obtain expressions for angular distributions of charged leptons arising from the interference of the four-point contribution with the standard-model contribution. We take into account possible longitudinal or transverse beam polarization likely to be available at a linear collider. We examine several correlations which can be used to study the various form factors present in the ${e}^{+}{e}^{\ensuremath{-}}HZ$ contact interactions. We also obtain the sensitivity of these correlations in constraining the new-physics interactions at a linear collider operating at a center-of-mass energy of 500 GeV with longitudinal or transverse polarization.