微扰QCD因子化方案下的B介子三体衰变

B three-body decays in perturbative QCD factorization approach

运用微扰QCD因子化方案,考虑Sudakov因子对长程部分的压低作用,引入双强子分布振幅等非微扰参数,利用Flatte和Briet-Wigner模型对类时形状因子进行参数化处理,加入顶角修正,微扰计算经共振态f0(500,980,1500,1790)的B^+→π^+π^-π^+三体衰变分支比,结果分别为6.41×10^-9,1.25×10^-7,1.92×10^-8,5.66×10^-9.目前实验上给出分支比Br(B^+→π^+f0(980)[π^+π^-])的上限数据是1.5×10^-6.对比实验结果表明,在考虑ss的贡献和顶角修正项后,该文计算较前期结果更加合理,其中ss的贡献是差别的主要来源,不容忽略.

We calculate the branching ratio of B three-body decay to f0(500,980,1500,1790)resonance in perturbative QCD factorization approach with the two-hadron distribution amplitude input parameter.The Flatte and the Breit-Wigner models are adopted to parameterize the time-like scalar form factors.The Sudakov form factors suppress the soft dynamics effectively,and make the perturbative calculation possible.We get the results 6.41×10^-9,1.25×10^-7,1.92×10^-8,5.66×10^-9 respectively.For the decay Br(B^+→π^+f0(980)[π^+π^-]),the pQCD prediction agrees very well with currently available experimental upper limits,1.5×10^-6.Compared with the experimental data,we can see that the calculation including vertex corrections and ss component contribution are more accurate and reliable than the results before,and the main changes come from the ss component contribution.