Search for CP Violation in the tau Lepton Decays.

寻找 tau 轻子衰变中的 CP 破坏。

基本信息

批准号：
12640277
负责人：
HAYASHI Hisaki
金额：
$ 1.47万
依托单位：
Nara Women's University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2003
项目状态：
已结题

项目摘要

In this research project, we have studied the various properties of the tau lepton using the large amount of tau sample accumulated by the Belle detector in the electron-positron storage ring (KEKB) at KEK, Japan. The KEKB is the highest luminosity machine in the world, which recently achieves to the value of 1.0x10^<34>/cm^2/sec^2. Using the large amount of tau-lepton sample, the topics we have studied include;1)Search for CP violation in tau decays (paper(1))2)Search for Electric Dipole Moment of tau lepton (paper (4),(5));3)Search for Lepton-Flavor-Violating decays (paper (2),(7),(8),(9));4)Measurement of the 2π spectral function in the decay τ→ππν(paper (6)).In the items 1) and 2), we carried out the search for the CP-violating phenomena in the tau-decay processes and in the tau-pair production. In 3), we have searched for the lepton-flavor-violation(LFV) decays for various decays modes including τ→μγ、μη、μμμ、μee. While LFV decays are not observed yet, we obtained new upper limits in the range 1-3x10^-7 at 90% confidence level using 80-130/fb data. These limits improve the previous results by one order of magnitude and provide the limit to the theoretical models based on SUSY and right-handed heavy neutrinos.The 2pi spectral function in 4) is the important observable to improve the theoretical prediction of the muon anomalous magnetic moment (g-2), where the largest uncertainty exists in the hadronic vacuum polarization term. In order to make the precise measurement, careful checks are carried out on the various detector effects including pi0 efficiency, triggers and background. The preliminary results are presented in the paper (6) and we are now preparing a full paper for this research.

在该研究项目中，我们使用了日本Kek的电子峰值存储环（KEKB）中Belle探测器积累的大量Tau样品研究了Tau Lepton的各种特性。 KEKB是世界上最高的发光机器，最近达到1.0x10^<34>/cm^2/sec^2的值。 Using the large amount of tau-lepton sample, the topics we have studied include;1)Search for CP violation in tau decays (paper(1))2)Search for Electric Dipole Moment of tau lepton (paper (4),(5));3)Search for Lepton-Flavor-Violating decays (paper (2),(7),(8),(9));4)Measurement of the 2π spectral function in the decay τ→ππν（纸（6））。在项目1）和2）中，在tau-decay过程和tau-pair生产中进行了搜索CP侵入现象。在3）中，我们已经搜索了各种衰变模式的Lepton-Flavor-Favor-侵入（LFV）衰变，包括τ→μγ，μη，μμm，μεμε。尽管尚未观察到LFV衰减，但使用80-130/fb数据在90％的置信度下，我们在1-3x10^-7的范围内获得了新的上限。这些限制将先前的结果提高了一个数量级，并为基于SUSY和右手重型神经的理论模型提供了极限。4）中的2PI光谱函数是提高MUON异常磁矩（G-2）的理论预测的重要意见，其中最大的不确定是在Hadreonic valium Ideligation dolareviental dolarvilly dolarevilition Term中存在的。为了进行精确测量，对各种检测器效应进行了仔细检查，包括PI0效率，触发器和背景。初步结果在论文（6）中提出，我们现在正在为这项研究准备完整的论文。