Study of T-invariance in K^+ Decay at KEK Proton Synchrotron

KEK 质子同步加速器 K^ 衰变中 T 不变性的研究

基本信息

批准号：
06044216
负责人：
IMAZATO Jun
金额：
$ 3.65万
依托单位：
National Laboratory for High Energy Physics (KEK)
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06044216/
关键词：
Time Reversal Invariance K-meson Decay Muou Polarization Proton Synchrotron Superconducting Spectrometer Stopped Muou CsI(Tl)sciutillata Fiber Target K^+崩壊 Tの破れ CsI(Tl)ポラリメータ

项目摘要

The purpose of this project is to study the problem of time reversal invariance (TRI) and to search for its violation in a kaon decay process K^+ *pi^0mu^+nu.We looked for transverse muon polarization which indicates violation of TRI by using the Superconducting Toroidal Spectrometer at the KEK proton synchrotron. This study can shed light to the origin of CP-violation which is one of the important issues of the present particle physics.This project was carried out by an international collaboration of Japan, Russia (Instutute for Nuclear Research, Russian Academy of Sciences) and Canada (TRIUMF and others).Although the experiment itself is one of the KEK-PS experiments, we spent years to construct and preapre the detector by international cooperative work, because the size of the experiment is large.In 1995 experimental apparatus was completed and measurement was started.The one of the mail elemens of the detector is a photon detector to detect pi^0 from the K^+*pi^0mu^+nu decay.This d … More etector is comprise 768 CsI(Tl) crystals and was designed by Japan-Russia collaboration.The crystals were produced at Kharikov in Ukraina under the conduct of INR,and brought to KEK where further preparation has been done. A barrel of CsI(Tl) was completed in 1995 and was installed at the Toroidal Spectrometer in last September after a careful test, tuning and a calibration measurement.An active target and one of the tracking chambers, C1, have been made by the Japan-Canada collaboration.They were assembled at the TRIUNF shop and brought to KEK last summer.They were also installed in the setup and tuned.The whole experimental apparatus became ready in last fall and the test and tuning of the system was started using K^+ beam from K5 at KEK-PS.The gain adjustment of CsI(Tl) crystals was performed by the measurement of K^+*pi^0pi^+ and K^+*mu^+nu decays.The measurement was also done for the design of the muon polarimeter, such as the degrader thickness.The positron counters were carefully aligned and their threshold was tuned.After these preparation measurements, a real measurement of the muon polarization started in January 1996.The measurement will continue further in next fiscal year to get enough statistical accurscy in the result.But we started the analysis of taken data. Less

该项目的目的是研究时间反转不变性（TRI）问题，并在 kaon 衰变过程 K^+ *pi^0mu^+nu 中寻找其违反情况。我们寻找表明违反 TRI 的横向 μ 子极化通过使用 KEK 质子同步加速器上的超导环形光谱仪，这项研究可以揭示 CP 破坏的起源，这是当前粒子物理学的重要问题之一。由日本、俄罗斯（俄罗斯科学院核研究所）和加拿大（TRIUMF 等）国际合作完成。虽然该实验本身是 KEK-PS 实验之一，但我们花了数年时间来构建和准备探测器由于实验规模较大，由国际合作完成。1995年实验装置完成并开始测量。探测器的主要元件之一是光子探测器，用于从K^+*pi^0mu^+nu 衰变。该探测器由 768 个 CsI(Tl) 晶体组成，由日俄合作设计。晶体在 INR 的指导下在乌克兰 Kharikov 生产，并带来到 KEK，进一步的准备工作已于 1995 年完成，并于去年 9 月在经过仔细测试、调整和安装后安装在环形光谱仪上。校准测量。主动目标和跟踪室之一 C1 是由日本和加拿大合作制造的。它们在 TRUNF 车间组装，并于去年夏天带到 KEK。它们也安装在装置中并进行了调谐。整个实验装置于去年秋天准备就绪，并使用来自 KEK-PS 的 K5 的 K^+ 光束开始了系统的测试和调谐。CsI(Tl) 晶体的增益调整是通过测量K^+*pi^0pi^+ 和 K^+*mu^+nu 衰减。测量还针对 μ 子旋光计的设计进行，例如衰减器厚度。仔细对准正电子计数器并调整其阈值经过这些准备测量，μ子极化的实际测量于1996年1月开始。测量将在下一个财政年度继续进行，以获得足够的统计精度。但我们开始对所获取的数据进行分析。