The two-photon width Gamma(gamma gamma) of the eta(c) meson has been measur
ed 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(+/-)pi(-/+), K(+)K(-)pi(0
), pi(+)pi(-)eta, pi(+)pi(-)eta', and rho(+)rho(-) using an integrated lumi
nosity of 140 pb(-1) at root s similar or equal to 91 GeV and of 52 pb(-1)
at root s similar or equal to 183 GeV. The result is Gamma(gamma gamma)(eta
(c)) = 6.9 +/- 1.7 star +/- 0.8 sys +/- 2.0(BR) keV. The Q(2) dependence of
the eta(c) cross section is studied for Q(2) < 9 GeV2. It is found to be b
etter described by a Vector Meson Dominance model form factor with a J-pole
than with a rho-pole. In addition, a signal of 29 +/- 11 events is observe
d at the chi(c0) mass. Upper limits for the two-photon widths of the chi(c0
), chi(c2) and eta(c)' are also given. (C) 1999 Elsevier Science B.V. All r
ights reserved.