分类: 物理学 >> 凝聚态:结构、力学和热性能 提交时间: 2017-03-26
摘要: The theoretical explanations about the "ρπ puzzle" in charmonium decays are reviewed exten-sively, and the comparison of theoretical predications with experimental data is made whenever possible. Three methods to estimate the ratio of the branching fractions of J/ψ and ψ′decays are also discussed. It is pointed out that in order to understand the ρπ puzzle, and the dynamics of charmonium decays, systematic studies should be made in theory, phenomenology and experiment aspects.
分类: 物理学 >> 凝聚态:结构、力学和热性能 提交时间: 2017-03-26
摘要: On the basis of the study of inclusive hadronic events, two methods are adopted to determine the number of produced ψ(2S) events collected by BES in 2001-2002 run, which is 14:0 £ 106 with the uncertainty of 4%.
分类: 物理学 >> 凝聚态:结构、力学和热性能 提交时间: 2017-03-26
摘要: The branching fraction of the ψ" decays into charmless final states is estimated in the S- and D-wave charmonia mixing scheme. With the information of the hadronic decays of J/ψ and ψ', it is found that a large branching fraction, up to 13% of the total ψ" decays, may go to charmless final states. The experimental search for these decays is also discussed.
分类: 物理学 >> 凝聚态:结构、力学和热性能 提交时间: 2017-03-26
摘要: Adding to the long standing “ρπ puzzle” in ψ′and J/ψ decays, recently BEijing Spectrometer (BES) reported B(ψ′→ K0SK0L) which is enhanced relative to the pQCD “12% rule” expectation from B(J/ψ → K0SK0L). If the enhancement is due to the mixing of the S- and D-wave charmonium states as in the ρπ case, the newly measured B(ψ′ → K0SK0L) gives a constraint on B(ψ″ → K0SK0L).It erves as a good test for the scenario of the S- and D-wave mixing in the ψ′and ψ″.
分类: 物理学 >> 凝聚态:结构、力学和热性能 提交时间: 2017-03-26
摘要: e+e− experiments at charmonium production threshold are reviewed, it is found that the contribution of the continuum process via virtual photon has been neglected in almost all the experiments and most channels analyzed. It is pointed out that the contribution of the continuum part may affect the final results significantly in ψ(2S) and ψ(3770) decays, while the interference between the continuum amplitude and the resonance amplitude may even affect the J/ψ decays as well as the ψ(2S) and ψ(3770). This leads to the revise of the analysis of strong and electromagnetic amplitude in ψ(2S) decays, including ψ(2S) → V P which is the long lasting puzzle between J/ψ and ψ(2S) decays. For ψ(3770) physics, a large constructive interference for light hadron modes and destructive interference for DD could be responsible for the discrepancy between the larger cross section of inclusive hadrons by direct measurement of e+e− → ψ(3770) → hadrons than the DD cross section measured using D single-tag and double-tag method.
分类: 物理学 >> 凝聚态:结构、力学和热性能 提交时间: 2017-03-26
摘要: The continuum one-photon annihilation at ψ(2S) in e+e-experiment is studied. Such contributions to the measured final state ωπ0 and π+π- at ψ(2S) mass are estimated by phenomenological models. It is found that these contributions must be taken into account in the determination of branching ratios of ψ(2S) →ωπ0 and ψ(2S) → π+π- , as well as other electromagnetic decay modes. The study eaches the conclusion that in order for BES to obtain the correct branching ratios on these decay modes, at least 10pb-1 of data below the ψ(2S) peak is needed.