On the choice of beam polarization in e^+e^-rightarrow ZZ/Zgamma and anomalous triple gauge-boson couplings

Abstract

The anomalous trilinear gauge couplings of Z and gamma are studied in e^+e^-rightarrow ZZ/Zgamma with longitudinal beam polarizations using a complete set of polarization asymmetries for the Z boson. We quantify the goodness of the beam polarization in terms of the likelihood and find the best choice of e^- and e^+ polarizations to be (+0.16, -0.16), (+0.09, -0.10) and (+0.12, -0.12) for ZZ, Zgamma and combined processes, respectively. Simultaneous limits on anomalous couplings are obtained for these choices of beam polarizations using Markov-Chain–Monte-Carlo (MCMC) for an e^+e^- collider running at sqrt{s}=500 GeV and mathscr {L}=100 fb^{-1}. We find the simultaneous limits for these beam polarizations to be comparable with each other and also comparable with the unpolarized beam case.