Observation ofηc′Production inγγFusion at CLEO

Abstract

We report on the observation of the eta(')(c)(2(1)S0), the radial excitation of the eta(c)(1(1)S0) ground state of charmonium, in the two-photon fusion reaction gammagamma-->eta(')(c)-->K(0)(S)K+/-pi(-/+) in 13.6 fb(-1) of CLEO II/II.V 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 1S0 and 3S1 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.

Study of charmonium production in $${b} $$ b -hadron decays and first evidence for the decay $${{{B}} ^0_{{s}}} \!\rightarrow \phi \phi \phi $$ B s 0 → ϕ ϕ ϕ

“…[14], were performed with two-photon pro- The properties of the η c (2S) state are less well studied. Measurements at the CLEO [55], BaBar [56,57], Belle [51,58] and BES III [59,60] experiments, using γ γ → η c (2S) → hadrons, double charmonium production in e + e − annihilation, exclusive B decays and radiative transitions of ψ(2S), yield the world averages [14] of 3639.4 ± 1.3 MeV for the η c (2S) mass, and 11.3 +3.2 −2.9 MeV for its natural width. Table 5 presents measurements of the masses of the η c and χ c states and of the natural width of the η c (1S) from the fit of the φφ invariant mass spectrum in Fig.…”

First Observation of theM1Transitionψ(3686)→γηc(2SAblikim1, Ачасов2, Ambrose3 et al. 2012Phys. Rev. Lett.Self Cite33180View full textAdd to dashboardCite

“…week ending 27 JULY 2012 042003-2 [4,5], and in the double-charmonium production process e þ e À ! J=c c " c [6,7].…”

Bottomonium physics above BB¯ thresholds with the Belle experiment

“…Summary of the experimental measurements of the 1S hyperfine splitting in charmonium. γγ → η b → hadrons (red points): a) CLEO [48], b) Belle [49], c) BaBar [50], d) BaBar [51], e) Belle [52]. B → η b X (blue points): f) BaBar [53], g) Belle [54].…”