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Study of B-meson decays at the KEKB-Factory

KEKB 工厂 B 介子衰变研究

基本信息

批准号：
13440083
负责人：
TAKASAKI Fumihiko
金额：
$ 10.43万
依托单位：
Institute of Particle and Nuclear Studies (2004)The High Energy Accelerator Research Organization (2001-2003)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2004
项目状态：
已结题

项目摘要

In the Particle Physics, a picture based on three doublets of quarks, proposed by Kobayashi and Maskawa, is so successful that it is conceived as a part of the "Standard Model" of Particles. Originally Kobayashi-Maskawa theory was introduced in 1973 to explain the CP violation observed in the K-meson decays. The most crucial and convincing way of proving the Kobayashi-Maskawa theory is to find the CP violation in the processes other than the K-meson decays. Sanda and Bigi noticed that the effects of CP violation can be large and measurable if the life time is long enough and if the B-meson mixing is large. It turned out that this is really the case and the serious study has started in late 1980s to measure this effect experimentally.A B-meson factory was constructed along this line of consideration and the experiment has started in 1999. The performance of the accelerator has been improving steadily and its luminosity exceeded the design goal and it is now the world best colliding beam … More accelerator ever built.Along with the superb performance of the accelerator, the Belle experiment has been operated as it was designed and produces more that 400 million B-meson pairs by the end of March 2005. Thanks to the huge data sample, the Belle experiment has successfully observed the CP violation in 2001 as was proposed by Sanda and Bigi. This provides a very stringent basis for claiming the correctness of the Kobayashi-Maskawa theory, The Belle collaboration has already published more than 120 scientific papers in the refereed journals. The study by the Belle experiment has started to search for effects which may hint the existence of something beyond the standard model.The success of the Belle experiment is due to the excellent performance of the Belle detector, especially its Vertex detector to measure the B-meson lifetime accurately. This detector has been built, operated and improved by the international team of the Belle collaboration.The key of the success is also due to the excellent performance of the calorimeter to measure accurately the energy of photons and electrons produced Less

在《粒子物理学》中，小林和Maskawa提出的基于三对夸克的图像是如此成功，以至于它被认为是粒子“标准模型”的一部分。Kobayashi-Maskawa理论最初是在1973年引入的，用来解释在K介子衰变中观察到的CP破坏。证明Kobayashi-Maskawa理论的最关键和最有说服力的方法是在K介子衰变以外的过程中发现CP破坏。Sanda和Bigi注意到，如果寿命足够长，B介子混合很大，CP破坏的影响可以很大且可测量。事实证明，这是真的，从20世纪80年代后期开始了认真的研究，以实验测量这种效应。沿着这一思路，沿着建造了一个B介子工厂，并于1999年开始实验。加速器的性能不断提高，其亮度超过了设计目标，是目前世界上最好的对撞机 ...更多信息沿着该加速器的卓越性能，贝儿实验已按设计运行，到2005年3月底产生了4亿多个B介子对。2001年，贝儿实验成功地观测到了Sanda和Bigi提出的CP破坏。这为主张Kobayashi-Maskawa理论的正确性提供了非常严格的依据，贝儿合作已经在被评审的期刊上发表了120多篇科学论文。贝儿实验的研究已经开始寻找可能暗示标准模型之外的东西存在的效应，贝儿实验的成功是由于贝儿探测器的优异性能，特别是它的Vertex探测器精确测量了B介子的寿命。这台探测器由贝儿合作的国际团队负责建造、运行和改进，成功的关键也是由于量热计的优异性能，能够精确测量产生的光子和电子的能量，少