Observation of $\eta_c(1S)$ and $\eta_c(2S)$ decays to $K^+ K^- \pi^+ \pi^- \pi^0$ in two-photon interactions

We study the processes gamma gamma -> K-S(0) K-+ pi(-+) and gamma gamma -> K+K- pi(+)pi(-)pi(0) using a data sample of 519: 2fb(-1) recorded by the BABAR detector at the PEP-II asymmetric-energy e(+)e(-) collider at center-of-mass energies near the Y(nS) (n = 2, 3, 4) resonances. We observe the eta(c) (1S), chi(c0) (1P) and eta(c) (2S) resonances produced in two-photon interactions and decaying to K+K- pi(+)pi(-)pi(0), with significances of 18.1, 5.4 and 5.3 standard deviations (including systematic errors), respectively, and report 4.0 sigma evidence of the X-c2(1P) decay to this final state. We measure the eta(c)(2S) mass and width in K-S(0) K+- pi(+-) decays, and obtain the values m(eta(c)(2S)) = 3638: 5 +/- 1.5 +/- 0.8 MeV/c(2) and Gamma(eta(c)(2S)) = 13.4 +/- 4: 6 +/- 3.2 MeV, where the first uncertainty is statistical and the second is systematic. We measure the two-photon width times branching fraction for the reported resonance signals, and search for the X-c2 (2P) resonance, but no significant signal is observed.