Study of kaon decays using stopped positive kaons at the KEK proton synchrotron

使用 KEK 质子同步加速器中停止的正 kaon 进行 kaon 衰变研究

基本信息

批准号：
14540285
负责人：
IMAZATO Jun
金额：
$ 2.11万
依托单位：
High Energy Accelerator Research Organization (2004)The High Energy Accelerator Research Organization (2002-2003)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

In this research program two experiments of E246 'Search for T-violating transverse muon polarization' and E470 "Branching ratio measurement of K^+ → π^0π^+γ decay direct emission" were performed at the KEK proton synchrotron. The transverse polarization, P_T, which is T-odd in nature, is an important quantity related to CP violation. Since there is no contribution to PT from the standard model, It is a very sensitive probe of new physics beyond the standard model. In the present work careful data analysis was performed for the data which had already been taken by 2000 and systematic error were thoroughly studied. A final result of transverse polarization and its physics parameter Imξ were obtained as P_T = -0.0017 ±0.0023 (stat) ±0.0011 (syst), and Imξ = -0.0055 ±0.0071 (stat) ±0.0036 (syst), which were consistent with zero revealing no T violation. In the E470 experiment the direct emission component of K^+ →π^0π^+γ which is a chiral anomaly transition was extracted in a precise spec … More tral measurement. From about 4,000 extracted events, the branching ratio was determined to be BR(DE) = (6.1±2.5(stat) ±1.9(syst))X10^<-3> which was consistent with the recent BNL result but contradicting previous in-flight decay data. As a byproduct the K^+→π^0π^0e^+ν decay was studied, and from exracted 216 events a form factor was determined although the statistical accuracy was still not good, and formalism was established to deduce the π-π scattering length.The possibilities of kaon decay experiments to use stopped K^+ beam at J-PARC, now under construction, were investigated. Since one expects 100 times higher beam intensity there, not only quantitative but also qualitative improvements and developments of data will be pursued. Regarding the T-violation muon polarization experiment, it will become important to measure not only the K^+ →π^0μ^+ν decay but also the K^+→μ^+νγ decay, which are complementary in some theoretical models of CP violation. New detector systems were investigated and several decay channels were studied with their physics cases. Less

在该研究计划中，在Kek Proton Synchrotron上，进行了E246'搜索T-violation Tribating Tribating Triveration横向隆隆化极化'和E470“分支比测量的分支比测量”。本质上是T-ODD的横向极化P_T是与CP违规有关的重要数量。由于标准模型对PT没有贡献，因此除了标准模型之外，它是对新物理学的非常敏感的探测。在本工作中，对2000年已经处理的数据进行了仔细的数据分析，并且系统误差已彻底研究。横向极化及其物理参数IMξ的最终结果是作为P_T = -0.0017±0.0023（STAT）±0.0011（SYST）（SYST），IMPO = -0.0055±0.0071（STAT）（STAT）±0.0036（SYST）（SYST），与零揭示了零违规的均一致。在E470实验中，以精确的规格提取了k^+→π^0π^+γ的直接发射成分，这是手性异常的转变。从大约4,000个提取的事件中，分支比为BR（DE）=（6.1±2.5（stat）±1.9（Syst））X10^<-3>，这与最近的BNL结果一致，但与以前的飞行中衰减数据相矛盾。作为副产物，研究了K^+→π^0π^0e^0e^+ν衰减，并且从执行的216个事件中，尽管统计准确性仍然不好，并且确定了形式，并建立了形式，以推断出π-π散射长度。在j-parc上使用Kaon decay实验的可能性，现在调查了Kaon decay实验的可能性。由于人们期望那里的光束强度更高，因此将不仅进行定量，而且还会追求定性的改进和发展的发展。关于T侵入性元偏振实验，不仅要测量K^+→π^0μ^+ν衰变，还要测量K^+→μ^+νγ衰减，这在某些理论上的CP违反理论模型中都是完整的。研究了新的检测器系统，并研究了几个衰减通道的物理病例。较少的