We reanalyze the published data on the Y(4630)→ΛcΛ̄c and the Y(4660)→ψ(2S)ππ with a consistent ansatz and we find that the two observations are likely to be due to the same state YB, produced via initial state radiation (ISR), with MYB=4660.7±8.7MeV and ΓYB=61±23MeV. Under this hypothesis and reanalyzing the e+e-→J/ψππγISR spectrum we find B(YB→ΛcΛ̄c)/B(YB→ψ(2S)ππ)=117±44, B(YB→J/ψππ)/B(YB→ψ(2S)ππ)<0.46@90% C.L., B(Y(4350)→J/ψππ)/B(Y(4350)→ψ(2S)ππ)<3.4×10-3@90% C.L., and B(YB→ψ(2S)σ)/B(YB→ψ(2S)f0)=2.0±0.3. These conclusions strongly support the hypothesis of YB being the first observation of a charmed baryonium constituted by four quarks. Analyzing the mass spectrum we show that Y(4350) and YB are, respectively, consistent with the ground state and first radial excitation of the ℓ=1 state.
Physical Review Letters
- Pub Date:
- April 2010
- Glueball and nonstandard multi-quark/gluon states;
- Hadron-induced low- and intermediate-energy reactions and scattering;
- High Energy Physics - Phenomenology
- Corrected phase space normalization in the fits