节点文献
BESⅢ上D物理的相关研究
Studies of D Physics on BSEⅢ
【作者】 刘佩莲；
【作者基本信息】 山东大学 ， 粒子物理与原子核物理， 2014， 博士
【摘要】 北京谱仪(BESⅢ)在J/ψ、ψ(2S)、ψ(3770)、ψ(4040)等多个能量点获取了世界上最大统计量的数据样本,为r-粲能区物理的详细研究提供了条件和机遇。本论文主要介绍对D+s→η’ρ+及D+s→η’X分支比的测量。基于BESⅢ在(?)s=4.009GeV处采集的亮度为0.482fb-1的ψ(4040)数据,对ψ(4040)产生的Ds+D-s对进行研究。使用“单标记”的方法,测得B(Ds+→η’ρ+)=(5.6±1.4)%；使用“双标记”的方法,测得B(Ds+→η’X)=(9.1±2.0±0.5)%。 B(Ds+→η’ρ)的测量结果远远小于世界平均值(PDG2012)(12.5±2.2)%；B(Ds+→η’X)的测量结果与世界平均值(11.7±1.8)%在误差内一致。基于我们测量的B(Ds+→η’ρ+)及其它实验对DS的含有η’末态的分支比的测量,得到B(η’K)+B(η’π+)+B(η’ρ+)+B(η’l+vl)=(11.7±1.3)%(遍举方法),该结果与B(Ds+→η’X)(单举方法)的测量结果是相恰的。本分析为理解和认识PDG中遍举方法和单举方法得到的B(D+s→η’X)不一致的问题提供了重要的实验依据,另外还可用来检验与DS衰变相关的各种理论模型及参数化方法的正确性,以及为包含胶球成份的η-η’混合模型提供实验依据。另外,还介绍了本作者参与的工作：D0/D0→K-π+两过程的强相位差δKπ的测量。基于BESⅢ上获取的世界上最大的2.9fb-1ψ(3770)数据样本,利用ψ(3770)→D0D0衰变过程中两个D的量子关联效应,测得了目前世界上最精确的δKπ。该测量对D0和D0混合参数的测量及CKM矩阵幺正性的检验有重要意义。
【Abstract】 Beijing Spectrometer(BES Ⅲ)has collected data samples at several different energy points,such as J/ψ,ψ(2S),ψ(3770)and ψ(4040).And continuum data at3.650GeV were also collected.All these data samples can be used to study the physical topics at τ-charm energy region.In this thesis,we introduce measurements of the branching fractions for D+s→η’ρ+and Ds+→η’X.Based on a sample of0.482fb-1data taken at (?)s=4.009GeV, we study the D+sD-s pairs decaying fromψ(4040).With the "single" tag method,we measured B(D+s+→η’ρ+)=(5.6±1.4)%；with "double tag" method,we measured召(D+s→η’X)=(9.1士2.0±0.5)%.Our measured B(Ds+→p+)is much d-ifferent from the world average(12.5±2.2)%,and our measured B(D+s→η’X)is consistent with the world average(11.7±1.8)%within uncertainty.Based on our measured B(D+s→η’ρ+)and the fractions of other D+s modes with η’ measured by CLEO,we get B(η’K+)+B(η’π+)+B(η’ρ+)+)+B(η’l+νl)=(11.7±1.3)%(exclusive method),which is consistent with the inclusively measured B(D+s→η’X)within er-ror.This analysis resolves the puzzle in PDG:the world averages of B(Ds+→η’X) obtained with inclusive and exclusive method are not consistent. And,the measure-ment is important for testing the theories relevant with Ds decays,and also is helpful for understanding the mixing of η and η’.In addition,this thesis reports a study on the strong phase difference δKπ between D00→K-π+and D0→K-π-+.With the world’s largest ψ(3770)data sample taken at (?)=3.773GeV,we determined the most precise result of δKπ in the world using the quantum coherence between pair-produced D0and D0in ψ(3770)→D0D0.The result is very important for measuring the mixing of D0and D0,and helpful for testing the unitaritv of CKM matrix.