Measuring the Beam Polarizations and the Luminosity at Photon-Photon Colliders

Abstract

We present methods to measure the beam polarizations and the luminosity of $\gamma \gamma$ colliders at TeV energy scale. The beam polarizations of a $\gamma \gamma$ collider can easily be monitored by comparing the numbers of events of the processes $\gamma \gamma$ $\rightarrow$ $\ell^+ \ell^-$ and $\gamma \gamma$ $\rightarrow$ $W^+ W^-$, where $\ell$ means $e$ or $\mu$. The luminosity of a $\gamma \gamma$ collider is also measurable by the event rate of $W$ boson pair productions and the light lepton pair productions.