Published in:
Physical Review Letters 92,14 (2004) 142001;
Link to original published article:
http://dx.doi.org/10.1103/PhysRevLett.92.142001
Abstract
We report on the observation of the eta(c)'(2(1)S(0)), the radial excitation of the eta(c)(1(1)S(0)) ground state of charmonium, in the two-photon fusion reaction gammagamma --> eta(c)' --> (KsK+/-)-K-0 pi(-/+) in 13.6 fb(-1) of CLEO II/ILV data and 13.1 fb(-1) of CLEO III data. We obtain M(eta(c)') = 3642.9 +/- 3.1 (stat) +/- 1.5(syst) MeV and M(eta(c)) = 2981.8 +/- 1.3(stat) +/- 1.5(syst) MeV. The corresponding values of hyperfine splittings between S-1(0) and S-3(1) states are DeltaM(hf)(1S) = 115.1 +/- 2.0 MeV and DeltaM(hf)(2S) = 43.1 +/- 3.4 MeV. Assuming that the eta(c) and eta(c)' have equal branching fractions to K(s)Kpi, we obtain Gamma(gammagamma)(eta(c)') = 1.3 +/- 0.6 keV.
Keywords
detector;; quarkonia;; search;; eta(c);; lep
Date of this Version
January 2004