Branching Ratios of J/ψ→π03(π+π－)

The decay mode of J/ψ→π⁰3(π⁺π^－) was studied very little before. There are no informations except branching ratios for this channel in PDG book which based on less than 0.2×10⁶J/ψ events of MARKⅠ. Now, BESⅠ has a data sample of 7.8×10⁶J/ψ events, we can make more accurate results than MARKⅠ. Total of 3290±43 J/ψ→π⁰3(π⁺π^－) events including 1275±86 J/ψ→ω²(π⁺π^－) events are selected. J/ψ→π⁰3(π⁺π^－) and J/ψ→ω²(π⁺π^－) events have been generated with MC simulition for calculating events selection efficiency. BESⅠ result is: Br(J/ψ→π⁰3(π⁺π^－))=(2.52±0.06±0.43)% and Br(J/ψ→π⁰3(π⁺π^－))=(1.31±0.09±0.21)%. Meanwhile, we studied the invariant mass of 4π and ωππ to find interesting signals. It seems that there is a peak at about 1.74GeV in the invarianat mass spectrum of 4π, and a enhancement was also found at about 1.9GeV in the invariant mass spectrum of ωππ. It is not clear whether they are from resonances or background. Therefore, more work in detail is still going on.     

ΛΛ,ΛΛγ and ΛΛπ0 Productions in J/ψ Decay

The channels of J/ψ decay into,ΛΛ,ΛΛγ and ΛΛπ⁰ are analyzed with 7.8×10⁶ J/ψ events collected by BES detector at BEPC Collider.The branching ratios for three channels and the angular distribution for the first channel are measured.The branching ratios are Br(J/ψ→ΛΛ)=(l.08±0.06±0.24)×10^－3,Br(J/ψ→ΛΛγ)－4(90% CL)and Br(J/ψ→ΛΛπ⁰)=(2.3±0.7±0.8)×l0^－4 respectively. The angular distribution for J/ψ→ΛΛ is dN dcosθ=N₀(1+αcos²0),α=0.52±0.33±0.13.     

Simultaneous determination of 14β-lactam antibiotics in cosmetic products by liquid chromatography tandem mass spectrometry method

In this study,a simple and rapid high-performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS) method was established and validated to determine the 14β-lactam antibiotics in cosmetic products,including 1(ceftazidime),2(cefaclor), 3(cefdinir),4(ampicillin),5(cefalexin),6(ceftezole),7(cefotaxim),8(cefradine),9(cefuroxime),10(cephazoline),11 (cefathiamidine),12(cefoperazone),13(cafalotin),14(piperacillin).     

New Suppression Mode of the ψ(2S) Hadronic Decay

The hadronic decays ,and ωf2(1270) have been studied in a sample of 1.27 million produced.Measurements of their branching fractions are presented. While obeys the "14% rule" predicted by theory, →ωf2 (1270) is suppressed comparing with the corresponding decay. As a vector-tensor pair combination, the ωf2 mode is the first example of a non-vector-pseudoscalar decay of charmonium which violates the above mentioned rule.