On polarization parameters of spin-$1$ particles and anomalous couplings   in $e^+e^-\to ZZ/Z\gamma$
  We study the anomalous trilinear gauge couplings of $Z$ and $\gamma$ using a complete set of polarization asymmetries for the $Z$ boson in $e^+e^-\to ZZ/Z\gamma$ processes with unpolarized initial beams. We use these polarization asymmetries, along with the cross section, to obtain a simultaneous limit on all the anomalous couplings using the Markov-Chain--Monte-Carlo (MCMC) method. For an $e^+e^-$ collider running at $500$ GeV center-of-mass energy and $100$ fb$^{-1}$ of integrated luminosity the simultaneous limits on the anomalous couplings are $1\sim3\times 10^{-3}$. 
Rafiqul Rahaman, Ritesh K. Singh
hep-ph hep-ex