Ψ' 衰变中VP和PP模式的事例产生器

Event Generator for ψ＇Decays of VP and PP Modes

在北京谱仪（ＢＥＳ）原有模拟程序框架下，建立了适用于Ｊ／ψ，ψ’衰变到ＶＰ和ＰＰ模式、以及ψ→π~＋π~－Ｊ／ψ而后Ｊ／ψ衰变到ＶＰ和ＰＰ模式的事例产生器，考虑了相应的角分布，为Ｊ／ψ，ψ＇物理的研究提供了方便，在ψ＇→γη，γη＇，ωπ~０，π~＋π~－，Ｋ~＋，Ｋ~－等分支比的测量中，这一事例产生器可用于选择效率的确定和本底估计．

A convenient generator, based on the existing framework of BES simulation, applicable generally to both ψ＇ and J/ψ decays of VP and PP modes, is established. The corresponding angular distribution is taken into account. A similar generator is also established for the successive J/ψ decay in the process of ψ＇→X+ J/ψ. In the measurement of branching ratios for ψ＇→γη, γη＇, ωπ~o, π^+ π^-, K^+ K^-, this generator is used to determine the selection efficiency and estimate the background.