Observation of ηc(1S) and ηc(2S) decays to K+K- π+π-π0 in two-photon interactions

We study the processes γγ → KS0K±π± and γγ → K+K-π+π-π0 using a data sample of 519.2 fb-1 recorded by the BABAR detector at the PEP-II asymmetric-energy e+e- collider at center-of-mass energies near the Υ(nS) (n = 2, 3, 4) resonances. We observe the ηc(1S), χc0(1P), χc2(1P), and ηc(2S) resonances produced in two-photon interactions and decaying to K+K-π+π-π0, with significances of 18.1, 5.7, 5.2, and 5.3 standard deviations (including systematic errors), respectively. We measure the ηc(2S) mass and width in KS0K±π± decays, m(ηc(2S)) = 3638.5 ± 1.5 ± 0.8 MeV/c2 and Λ(ηc(2S)) = 13.4 ± 4.6 ± 3.2 MeV, where the first uncertainty is statistical and the second is systematic. We search for the Z(3930) resonance and find no significant signal. We also provide the two-photon width times branching fraction values for the observed resonances.