北京谱仪-Ⅲ上D^0介子半轻子衰变D^0→K^-e^+v_eπ^-e^+v_e的蒙特卡罗研究  

Monte Carlo Studies of the Semileptonic Decays for D^0→K^-e^+v_eπ^-e^+v_e at BES-Ⅲ

作　　者：李蕾[1] 荣刚[1] 马海龙[1] 

机构地区：[1]中科院高能物理研究所,北京100049

出　　处：《核电子学与探测技术》2010年第9期1230-1235,共6页Nuclear Electronics & Detection Technology

基　　金：国家自然科学基金(10935007);973计划基金(2009CB825200)

摘　　要：通过分析e+e-→Ψ(3770)→D,D衰变到所有可能末态的蒙特卡罗样本,模拟研究了实验测量D0介子半轻子衰变D0→K-e+ve,π-e+ve的绝对分支比。蒙特卡罗事例经过北京谱仪-Ⅲ(BES-Ⅲ)探测器进行了完整的模拟。基于完整的蒙特卡罗模拟样本及物理分析,研究了在BES-Ⅲ上测量D0→K-e+ve、π-e+ve衰变分支比所能够达到的精度。研究表明,如果利用BES-Ⅲ能够采集5(20)fb-1的Ψ(3770)数据,D0→K-e+ve,π-e+ve衰变分支比的测量精度可达到2.2(2.0)%及3.6(2.5)%。根据这两个过程分支比测量的精度,我们给出了实验测量D0介子半轻子衰变D0→K(π)-e+ve的形状因子f+K(π)(0)的测量精度。We simulate measurements of the absolute branching fractions for D0 meson semileptonic decays for D0→K-e＋veand D0→π-e＋ve by analyzing the Monte Carlo events generated for e＋e-→Ψ（3770）→D,where the DD-meson pairs are set to automatically decay to all possible final states.These Monte Carlo events are simulated in the BES-Ⅲ detector.Based on a full Monte Carlo simulation and full physics analysis,we study how well we can measure the absolute branching fractions for D0→K-e＋veand D0→π-e＋ve with the data to be collected with the BES-III detector at the BEPC-Ⅱ collider.We find that we can measure these branching fractions at the accuracy levels of 2.2（2.0）% and 3.6（2.5）% with ~5（20） fb-1 of Ψ（3770） data.Based on the simulated measurements of decay branching fractions,we also study at what precision levels we can measure the form factors f＋K（π）（0）.These measurements will be of great importance in more precisely testing the standard model.

关 键 词：半轻子衰变 测量精度 衰变分支比 形状因子 

分 类 号：O572.21[理学—粒子物理与原子核物理]