Formation of the ${\eta }_c$ in Two-Photon Collisions at LEP

L3 Collaboration

The two-photon width ${\Gamma }_{\gamma \gamma }$ of the ${\eta }_c$ meson has been measured with the L3 detector at LEP. The ${\eta }_c$ is studied in the decay modes ${\pi }^{+}{\pi }^{-}{\pi }^{+}{\pi }^{-}$, ${\pi }^{+}{\pi }^{-}$K${}^{+}$K${}^{-}$, K${}_s^0$K…