The Study Of Charmonium Decaying Into (?)K_S~0Σ~+

Beijing Electron Positron COllide(BEPC)and Beijing Spectrometer(BES) is an important τ-charm factory to produce J/ψ and ψ’.Basing on the data collected from BESⅢ,we can study J/ψ and ψ’ decay and measure their branching fractions,we also can search for baryon states such as N*、∑*and∧*and determine their mass、width and spin-parity by performing the partial wave analysis.So,it is important for us to study baryon excited states and learn more about J/ψ and ψ’ decaying.In this paper, we study J/ψ�'pKs0Σ++c.c and ψ’�'pKs0Σ++c.c by through events selection,background analysis and systematic errors analysis and so on.Finally,we measure their branch fractions respectively,and we also calculate the ratio of ψ’ and J/ψ decaying into pKs0Σ+to check the"12％" rule.We study the events of J/ψ�'pKs0Σ++c.c to find the baryon states N*and∑*in pKs0,Ks0∑mass spectrum.Which help us to learn more about baryon and provide more experimental evidences for developing the theory Of baryon.The branch fractions results are shown as the following, Br(J/ψ�'pKs0Σ+)=(1.55±0.04±0.08)×10-4Br(J/ψ�'pKs0Σ-)=(1.51±0.04±0.08)×10-4Br(ψ’�'pKs0Σ+)=(1.10±0.12±0.09)×10-5Br(ψ’�'pKs0Σ-)=(1.30±0.13±0.10)×10-5and the ratio of ψ’ and J/ψ decaying into pKs0Σ+is about Qh=(7.85±0.60)%.The work on this paper has two features.Firstly,the branch fractions of J/ψ�'pKs0Σ++c.c and ψ’�'pKs0Σ++c.c are measured for the first time. Secondly,some clear signals for excited baryon states are observed in pKs0,Ks0∑mass spectrum,which give us more information to learn the spectrum of baryon.