BESIII上tau 质量的高精度测量及相关研究

The high accurate tau mass measurement will be performed at the up-grated accelerator and detector (BEPCII/BESIII), which is the unique research base of high energy physics in Chinese. It is really a precious chance to improve the accuracy of tau mass, an important parameter of one of three elemantary leptons in the nature. At present, there exist many superiorities for this study, such as the recently constructed high accurate beam energy measurement system, the already taken colossal data sample, and the execellent software analysis enviroment. All these benefit the main contents of this project : 1) The total uncertainty of tau mass will be reduced from 0.2 MeV to 0.1 MeV；and the relative error at the level of six hundred-thousandths is anticipated, which is the unprecedented precision in the history of tau mass measurement. 2) The optimization technique used for tau mass scan is to be generalized to other scan experiments, such as measurements of charmonium resonance parameters. Moreover, the statistical basis for numerical results will be explored, and an extensive feasible scheme for scan experiments will be established. 3) The up-limit of tau mass measurement in electron-positron collider is to be evaluated in the light of the actually measured results and on the basis of the extensive Monte Carlo simulations.

依托国内唯一的加速器和谱仪(BEPCII/BESIII)，发挥最新建造完成的束流能量高精度测量系统，利用业已采集的大量数据样本以及良好的软件分析环境，首先，开展 tau 质量高精度测量，进一步提高作为自然界三个基本轻子之一粒子的质量精度，将现有误差0.2 MeV缩小一倍，达到0.1 MeV的水平；使得质量测量的相对精度达到十万分之六的水平。其次，将有关的统计优化技术推广应用于一般共振参数扫描实验的优化设计；并且逐步探究数值结果的理论基础，深化相应的数理统计方面的理论研究，建立具有普适意义的优化流程。最后，结合实际测量结果，在更深入更广泛的模拟实验基础上，开展正负电子对撞机tau 质量测量上限的研究。