BESⅢ上η→γπ^+π^-过程产生子的研究

Study on the event generator for η→γπ^+π^- at BESⅢ

根据手征微扰理论和矢量介子支配模型,构建了BESⅢ上η衰变到γπ+π-的蒙特卡罗产生子.蒙特卡罗模拟结果表明,末态粒子的角分布符合理论预期,光子的能量分布与实验数据非常一致,说明该产生子能够很好地描述η到γπ+π-的衰变过程.与相空间事例产生子相比,模拟数据与真实数据的一致性得到明显提高,这为今后BESⅢ实验开展η衰变研究提供了有利条件.

Based on the chiral perturbation theory and vector meson dominant model,we developed a Monte Carlo event generator for η→γπ＋π-decay. The Monte Carlo simulation shows that the angular distributions of the final states are consistent with the theoretical predictions and the energy distribution of the photon is in good agreement with experimental data,which indicates that this event generator could describe the decay of η→γπ＋π-very well. Comparing to the generator of phase space events,the significant improvement on the consistency between data and Monte Carlo simulation further proves the correctness of this generator,which is very useful to the study of eta decays at BESⅢ experiment in the near future.