Using a 478 pb-1 data sample collected with the BESIII detector operating at the Beijing Electron Positron Collider storage ring at a center-of-mass energy of √s=4.009 GeV, the production of e+e-→ηJ/ψ is observed for the first time with a statistical significance of greater than 10σ. The Born cross section is measured to be (32.1±2.8±1.3) pb, where the first error is statistical and the second systematic. Assuming the ηJ/ψ signal is from a hadronic transition of the ψ(4040), the fractional transition rate is determined to be B(ψ(4040)→ηJ/ψ)=(5.2±0.5±0.2±0.5)×10-3, where the first, second, and third errors are statistical, systematic, and the uncertainty from the ψ(4040) resonant parameters, respectively. The production of e+e-→π0J/ψ is searched for, but no significant signal is observed, and B(ψ(4040)→π0J/ψ)<2.8×10-4 is obtained at the 90% confidence level.
Observation of e+e-→ηJ/ψ at center-of-mass energy √s=4.009 GeV
DESTEFANIS, MARCO GIOVANNI;GRECO, Michela;MAGGIORA, MARCO;SPATARO, STEFANO GIOVANNI;
2012-01-01
Abstract
Using a 478 pb-1 data sample collected with the BESIII detector operating at the Beijing Electron Positron Collider storage ring at a center-of-mass energy of √s=4.009 GeV, the production of e+e-→ηJ/ψ is observed for the first time with a statistical significance of greater than 10σ. The Born cross section is measured to be (32.1±2.8±1.3) pb, where the first error is statistical and the second systematic. Assuming the ηJ/ψ signal is from a hadronic transition of the ψ(4040), the fractional transition rate is determined to be B(ψ(4040)→ηJ/ψ)=(5.2±0.5±0.2±0.5)×10-3, where the first, second, and third errors are statistical, systematic, and the uncertainty from the ψ(4040) resonant parameters, respectively. The production of e+e-→π0J/ψ is searched for, but no significant signal is observed, and B(ψ(4040)→π0J/ψ)<2.8×10-4 is obtained at the 90% confidence level.File | Dimensione | Formato | |
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