对Z^0三喷注事例中色联接敏感可观测量的研究  

Sensitive Observables for Color Connections in Three-Jet Events at Z0 Pole

作　　者：邵凤兰[1] 谢去病[1] 李世渊[1] 

机构地区：[1]山东大学物理与微电子学院,济南250100

出　　处：《高能物理与核物理》2003年第6期479-483,共5页High Energy Physics and Nuclear Physics

基　　金：国家自然科学基金 ( 10 0 75 0 31;10 2 0 5 0 0 9)资助

摘　　要：将末态部分子的色分离联接引入JETSET事例产生器 ,通过用喷注的DURHAM判据ycut及用喷注夹角限制事例形状 ,对Z0 衰变进行三喷注事例挑选 ,发现可以得到对色联接敏感的三喷注事例 .对于这类事例 ,末态强子的平均带电多重数及胶子喷注中的一系列可观测量对色联接的敏感性随ycut值的减小而增大 ;在小ycut值时 ,色中性流和色分离两种联接导致了显著差别 .使通过实验测量鉴别部分子的色联接成为可能 .By substituting the color separate singlet connections for the color neutral flow connections into JETSET7.4, we select the three-jet events according to DURHAM algorithm in e+e- annihilation at Z0 pole. We find that the ratio of the special three-jet events defined by constraining the angles between different jets is sensitive to different kinds of color connections. For these special events, different connections lead to significant differences for the charged particle multiplicity of events and properties of the gluon jet. The differences become larger as y cut getting smaller. By taking appropriate y cut, as 0.0005 in this paper, the differences between these two kinds of color connections should be discriminated by experiments.

关 键 词：Z^0 三喷注事例 色分离联接 DURHAM判据 色联接敏感 可观测量 喷注判据 末态部分子 QCD 量子色动力学 微扰 未态强子 胶子 JETSET事例产生器 

分 类 号：O572.21[理学—粒子物理与原子核物理]