LHCb实验上电荷宇称破坏相角γ的测量

电荷宇称破坏的精确测量是理解宇宙中正反物质不对称性的重要方式。相角γ是标准模型中描述电荷宇称破坏的CKM矩阵的复相角，也是CKM矩阵元中测量最不精确的参数之一，测量精度亟需提高。本项目将从两方面开展研究：利用新方法分析γ测量黄金道B+->DK+，D->Kspipi，提高其测量精度；利用新的Bs衰变道Bs->D(*)phi来测量γ，提升Bs衰变道γ测量的精度并理解B+衰变道及Bs衰变道γ测量结果的差异。研究将基于LHCb实验采集的9/fb的pp对撞数据以及BESIII实验采集的D0-D0-bar阈值的2.92/fb的正负电子对撞数据进行。本项目提出的研究内容均为首次进行，预期将极大的增加对电荷宇称破坏的理解。

Precision measurement of CP violation is one of the most important ways to understand the matter-antimatter asymmetry observed in the Universe. The CKM angle γ is the complex phase of the CKM matrix and is one of the least known quantities of the matrix. It is thus necessary to improve its precision for testing the CKM mechanism and for searching for new physics beyond the Standard Model. We propose to improve the precision on γ from two aspects: using a new method to improve the measurement of the golden channel B->DK, D->Kspipi and using new Bs decay modes Bs->D(*)phi to measure the angle γ. The studies will help improve the precision on γ and understand the difference observed between the B+ modes and Bs modes. The research is based on the 9/fb pp collision data collected by the LHCb experiment and 2.96/fb D0-D0-bar threshold data collected by the BESIII experiment. The methods proposed in the project are the first tries of their kinds and will shed new light on our understanding of CP violation.