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

We study the processes γγ→K[subscript S][superscript 0]K[superscript ±]π[superscript ∓] and γγ→K[superscript +]K[superscript -]π[superscript +]π[superscript -]π[superscript 0] using a data sample of 519.2fb[superscript -1] recorded by the BABAR detector at the PEP-II asymmetric-energy e[superscript +]e[superscript -] collider at center-of-mass energies near the Υ(nS) (n=2, 3, 4) resonances. We observe the η[subscript c](1S), χ[subscript c0](1P) and η[subscript c](2S) resonances produced in two-photon interactions and decaying to K[subscript S][superscript 0]K[superscript ±]π[superscript ∓], with significances of 18.1, 5.4 and 5.3 standard deviations (including systematic errors), respectively, and report 4.0σ evidence of the χ[subscript c2](1P) decay to this final state. We measure the η[subscript c](2S) mass and width in K[subscript S][subscript 0]K[subscript ±]π[subscript ∓] decays, and obtain the values m(η[subscript c](2S))=3638.5±1.5±0.8 MeV/c[superscript 2] and Γ(η[subscript 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 χ[subscript c2](2P) resonance, but no significant signal is observed.United States. Dept. of EnergyNational Science Foundation (U.S.)Natural Sciences and Engineering Research Council of Canada (NSERC)France. Commissariat à l'énergie atomiqueInstitut national de physique nucléaire et de physique des particulesGermany. Federal Ministry of Education and Research (BMBF)Deutsche Forschungsgemeinschaft (DFG)Istituto nazionale di fisica nucleare (INFN)Foundation for Fundamental Research on Matter (Netherlands)Research Council of NorwayMinistry of Education and Science of the Russian FederationSpain. Ministerio de Ciencia e Innovación (MICINN)Science and Technology Facilities Council (Great Britain