On the choice of beam polarization in $$e^+e^-\rightarrow ZZ/Z\gamma $$ e + e - → Z Z / Z γ and anomalous triple gauge-boson couplings

Abstract

Abstract The anomalous trilinear gauge couplings of Z and $$\gamma $$ γ are studied in $$e^+e^-\rightarrow ZZ/Z\gamma $$ e + e - → Z Z / Z γ 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 $$e^-$$ e - and $$e^+$$ e + polarizations to be ( $$+0.16$$ + 0.16 , $$-0.16$$ - 0.16 ), ( $$+0.09$$ + 0.09 , $$-0.10$$ - 0.10 ) and ( $$+0.12$$ + 0.12 , $$-0.12$$ - 0.12 ) for ZZ, $$Z\gamma $$ Z γ 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 $$e^+e^-$$ e + e - collider running at $$\sqrt{s}=500$$ s = 500 GeV and $$\mathscr {L}=100$$ L = 100 fb $$^{-1}$$ - 1 . We find the simultaneous limits for these beam polarizations to be comparable with each other and also comparable with the unpolarized beam case.