QCD因子化方法下_s→π^+π^-中湮没强度的探索  

Probe the Strength of Annihilation in _s→π^+π^- Decays with QCD Factorization

作　　者：鲁公儒[1] 苏方[1] 杨亚东[1] 郝红军[1] 

机构地区：[1]河南师范大学物理与信息工程学院,新乡453007

出　　处：《高能物理与核物理》2006年第6期501-506,共6页High Energy Physics and Nuclear Physics

基　　金：河南省杰出青年基金(0312001700)国家自然科学基金(10305003)资助~~

摘　　要：利用QCD因子化方法,并采用具有质量的有效胶子传播子来消除端点发散,计算了纯湮没衰变 Bs→π+π-过程的CP平均分支比并对该过程的CP破坏进行了具体研究．结果表明:该过程的CP平均分支比为1．24×10-7,同时企鹅图对该过程起着主要贡献;Bs→π+π-过程中直接CP破坏参数Cππ估算为-0．05,混合CP破坏参数Sππ比较大,可达到0．18．该过程在未来的LHC-b物理实验上是完全有可能被测量到的,通过对该过程的研究能够使我们更好地了解B介子无璨衰变的动力学机制和胶子的性质．Using the method of QCD factorization, we calculate the branching ratio and the CP violation for pure annihilation decay ￣Bs）→π^＋π^- in the Standard Model. Meanwhile, we employ an effective gluon mass resulted in the study of the infrared behaviour of gluon propagators to avoid the soft endpoint divergence. We find that the CP-averaged branching ratio is about 1.24×10^-7, and the penguin diagram contributions is dominant in this process. The direct CP violation parameter is about -0.05, while the mixing-induced CP asymmetry is a quite large number of 0.18. Once these quantities can be measured in the future LHC-b experiments, studying such a process will enrich our knowledge on the dynamics of the charmless hadronic decay of B-meson and the property of gluon.

关 键 词：QCD因子化 纯湮没衰变 分支比 CP破坏 

分 类 号：O572.2[理学—粒子物理与原子核物理] O156.1[理学—物理]