Recent results on light hadron spectroscopy from BES Ⅱ

We reported the observation of Y(2175) in φf0(980) mass spectrum in J/ψ→ηφf0(980) with f0(980)→π+π- and the observation of a broad 1-- resonance of K+K-mass in J/ψ→K+K-π0. The results from the partial wave analyses of Jψ→γπ+π- and γπ0π0, as well as J/ψ→pK-∧. are also presented.     

Recent results on hadron spectroscopy from BES

The BES-Ⅲ Detector is a very versatile multipurpose device located at the Institute of High Energy Physics （IHEP） in Beijing, China. Concerning the physics program it ties stringently up to the past BES and BES-Ⅱ experiments. Since start of the data taking in the middle of 2008 the accumulated dataset of 200.10^6 J/ψ events and 100.10^6 ψ＇ events already exceeds the world data on these resonances. In addition to studies of the charmonium systems the data offers great opportunity for investigations in the light hadron sector. In detail it will be reported about the confirmation of the enhancement in pp invariant mass in radiative J/ψ decays, the search for decays Y（2175） → K＊0K＊0, observation of a charged K^± in K^±π^0 and observation of a new excited baryon N＊（2065） decaying to pπ^0 and charged onjugate. The first result is based on data taken by BES-Ⅱ and BES-Ⅲ, the latter three on data collected by BES-Ⅱ only.     

线性σ模型和在J/ψ→γp(-p)的p(-p)质量谱中观测到的增强现象

假定BES合作组在辐射衰变J/ψ→γp(-p)中观测到的p(-p)谱的增强是由于存在一个pp的分子态,用线性σ模型计算了它的束缚能和寿命.具体考虑了这种增强现象是由于p(-p)可能形成一个S波或P波共振态,并把计算结果和实验数据做了比较.与氘核不同,由于p(-p)可以通过s道湮没,因此通过研究它的总宽度可以获得线性σ模型及其相关问题的信息.