0 Measurements of the Mass , Total Width and Two - photon Partial Width of the η c Meson
نویسندگان
چکیده
Using 13.4 fb of data collected with the CLEO detector at the Cornell Electron Storage Ring, we have observed 300 events for the two-photon production of ground-state pseudo-scalar charmonium in the decay ηc → K 0 SK π. We have measured the ηc mass to be (2980.4 ± 2.3 (stat) ± 0.6 (sys)) MeV and its full width as (27.0 ± 5.8 (stat) ± 1.4 (sys)) MeV. We have determined the two-photon partial width of the ηc meson to be (7.6 ± 0.8 (stat) ± 0.4 (sys) ± 2.3 (br)) keV, with the last uncertainty associated with the decay branching Permanent address: University of Cincinnati, Cincinnati, OH 45221 Permanent address: Massachusetts Institute of Technology, Cambridge, MA 02139.
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