MEASUREMENT OF CP VIOLATION PARAMETER USING RARE KAON DECAYS

使用稀有 KAON 衰变测量 CP 破坏参数

• 批准号: 13304020
• 负责人: YAMANAKA Taku
• 金额: $ 28.04万
• 依托单位: OSAKA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13304020/
• 关键词: cp violation; kaons; rare decay; 光電子増倍管

The decay KL→π^<0>νν is one of the best decays to measure the CP violation parameter.We prepared experiment KEK E391a to search for the decay with the best sensitivity, and started running in February 2004. The experiment will also serve as a pilot experiment for the next experiment to measure its branching ratio.We studied a new experiment for J-PARC 50GeV proton accelerator using Monte Carlo simulation. We found that the acceptance is increased by a factor 4 by utilizing the side of the decay region as a calorimeter. With the 10% of the design intensity of the accelerator, we can observe 150 signal events and measure the CP violation parameter with a 6% accuracy.We also developed a new calorimeter which can measure the incident angle of photons. This is a shashlik type detector with individual fibers reading one of the 3 different depth regions. A test experiment using 1.5-2.8GeV photons at SPring8 showed that it has an angle resolution of 9%/ Sqrt (E (GeV) ). The resolution can be improved further by increasing the light yield etc..We also developed a new type of light guide to inject the light from fibers to a phototube at a shallow incident angle. Using the light guide, the number of photoelectrons was increased by a factor 1.8.We also published results from Fermilab KTeV experiment, including the measurement of CP violation parameter, ε'/ε, establishing the direct CP violation.

衰减Kl→π^<0>νν是测量CP违规参数的最佳衰落之一。我们准备了实验Kek E391A以最佳的敏感性寻找衰变，并于2004年2月开始运行。实验还将作为下一个实验进行j ock的实验。仿真。我们发现，通过使用下降区域的一侧作为量热计，将接受度增加了因子4。有了10％的加速器设计强度，我们可以观察150个信号事件并以6％的精度测量CP违规参数。我们还开发了一种新的热量表，可以测量照片的入射角。这是一种Shashlik型检测器，单个纤维读取3个不同深度区域之一。在Spring8时使用1.5-2.8GEV照片的测试实验表明，其角度分辨率为9％/ sqrt（E（GEV））。可以通过增加光产率等来进一步改善分辨率。我们还开发了一种新型的光指南，以浅入射角将光从纤维注射到光电管。使用光指南，光电子的数量增加了一个因子1.8。我们还发表了Fermilab KTEV实验的结果，包括测量CP违规参数，ε'/ε，建立了直接的CP违规。

项目成果

A.Alavi Harati et al.: "Measurements of Direct CP Violation, CPT Symmetry, and Other Parameters in the Neutral Kaon System"Phys.Rev.. D67. 012005 (2003)

A.Alavi Harati 等人：“中性 Kaon 系统中直接 CP 破坏、CPT 对称性和其他参数的测量”Phys.Rev..D67。

A.Alavi-Harati et al.: "Measurements of the Decay K_L->e^+e^-μ^+μ^-"Physical Review Letters. 90. 141801 (2003)

A. Alavi-Harati 等人：“衰变 K_L->e^+e^-μ^+μ^- 的测量”《物理评论快报》90. 141801 (2003)

A.Alavi-Harati et al.: "Measurements of Direct CP Violation, and CPT Symmetry, and Othe rParameters in the Neutral Kaon System"Physical Review. D67. 012005 (2002)

A.Alavi-Harati 等人：“中性 Kaon 系统中直接 CP 破坏、CPT 对称性和其他参数的测量”物理评论。

A.Alavi Harati et al.: "Branching Ratio Measurement of the Decay K_L->e^+e^-"Phys. Rev. Lett.. 87. 111802 (2001)

A.Alavi Harati 等人：“衰变 K_L->e^ e^- 的分支比测量”Phys。

A.Alavi Harati et al.: "Measurements of the Rare Decay K_L->e^+e^-e^+e^-"Phys. Rev. Lett.. 86. 5425 (2001)

A.Alavi Harati 等人：“稀有衰变 K_L->e^ e^-e^ e^- 的测量”Phys。