R＆D on Experimental Search Methods on Strange B-Meson Decoys

奇异B介子诱饵实验搜索方法研发

• 批准号: 12640268
• 负责人: HAZUMI Masashi
• 金额: $ 0.77万
• 依托单位: High Energy Accelerator Research Organization (2001)Osaka University (2000)
• 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 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12640268/
• 关键词: B meson; rare decay; vertex detector; CP violation; ストレンジB中間子; 崩壊点検出器

The goal of this study is to optimize the detector design that is suitable for the measurements of rare decays of B mesons and strange B mesons, and clarify the effect of the optimization. In particular, the study tries to know how much the vertex resolution can be improved, and what kind of physics we can exploit with the improvement in electron-positron collisions. To this end, we first made a detailed study on the performance of the existing vertex detector at the KEK B-factory. The results were presented at an international conference. Then, as an upgrade, we considered a configuration with a beampipe with a radius of 1 cm, with two pixel-type sensors and wrth four layers of silicon strip detectors. With this configuration, the resolution can approximately be 1/3 of the present value. We have also confirmed that this configuration is a workable solution in terms of the background and the radiation damage. Using Monte Carlo simulation, we estimated improvements on various observables. As for strange B mesons, we find that there is no clear advantage of electron-positron coliders over the experiments with hadron beams. On the other hand, the improved vertex resolution reduces backgrounds in rare B meson decays drastically.We also had a very important discovery that was derived from this study ; we find a new method that uses B →ΦΦXs decays to search for a new CP-violating phase. This idea was presented at the Japan Physics Society meeting m Autumn 2001. Since the principle can also be applied to decays of strange B mesons and Lambda-B baryons, we need a systematic study in the future

这项研究的目的是优化适合于稀有B介子和奇怪B介子的罕见衰减的检测器设计，并阐明优化的效果。特别是，该研究试图知道可以改善顶点分辨率的数量，以及通过改进电子峰值碰撞的物理学，可以利用哪种物理学。为此，我们首先对KEK B-FARCTORY现有顶点检测器的性能进行了详细研究。结果是在国际会议上提出的。然后，作为升级，我们考虑了带有半径为1 cm的梁管，带有两个像素型传感器和四层硅条探测器的配置。通过这种配置，分辨率大约可以是现值的1/3。我们还确认，就背景和辐射损坏而言，这种配置是可行的解决方案。使用Monte Carlo模拟，我们估计了各种观察力的改进。至于奇怪的b介子，我们发现比起用强子梁进行了电子峰山脉山脉山脉相撞器的优势。另一方面，改进的顶点分辨率会大大减少稀有的B介子衰变的背景。我们也有一个非常重要的发现，这是从这项研究中得出的。我们找到了一种使用B→φφxs衰减的新方法来搜索新的CP侵入阶段。这个想法是在2001年秋季的日本物理协会会议上提出的。由于该原则也可以应用于奇怪的B梅森和Lambda-B Baryons的衰落，因此我们将来需要进行系统的研究

项目成果

Masashi Hazumi: "Performance of the Belle Silicon Vertex Detector"Nucl. Inter. and Meth.. A473. 1-6 (2001)

Masashi Hazumi：“Belle 硅顶点探测器的性能”Nucl。

Masashi Hazumi: "Performance of the Belk Silicon Vertex Detector"Nucl.Instr. and Meth.. A473. 1-6 (2001)

Masashi Hazumi：“Belk 硅顶点探测器的性能”Nucl.Instr.