Study of Elementary Particles Using OPAL Detector at LEP-II

使用 LEP-II OPAL 探测器进行基本粒子研究

基本信息

批准号：
09044060
负责人：
KOBAYASHI Tomio
金额：
$ 11.78万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09044060/
关键词：
CERN LEP-II OPAL experiment Leadglass calorimeter Standard Model W boson Higgs boson Supersymmetry ヒッグス粒子

项目摘要

The world highest energy e^+e^- collider LEP at CERN has started its operation in 1989. After completion in 1995 of highly successful physics program at the Z resonance, LEP has started the energy upgrade program LEP2 in. 1996, exceeding the collision energy sufficient to produce the W boson in pair. In 1997 the LEP collision energy was increased to 183 GeV and further pushed up to 189 0eV in 1998. The OPAL experiment, in which we have been playing a leading role, has successfully collected data at this new energy region. In order to make full use of these data, we worked on understanding the detector performance at high energy, precise calibration of the detector, developments for improved physics analysis technique to gain precision of measurements and sensitivity for searches, and we also pursued a number of new physics topics.1. About 4000 W pairs events have been collected. The production cross-section, total W width and decay branching ratios were precisely measured. Accurate measurement of the W mass, together with the precision results of the Z boson, provides information for crucial tests of the Standard Model. Based on the increased data sample of W pair events, precision of W mass determination has been largely improved.2. Systematic investigations were made for varieties of Standard Model processes such as fermion pair production, Z pair production, single W production and general four-fermion final states. The Standard Model is found to work well at this higher energy region.3. The mass of the Higgs boson, which is a key element of the Standard Model yet undetected, is found to be heavier than about 91 GeV.4. Searches for Supersymmetric particles were performed and improved limits on the parameters in the theory have been obtained.

CERN的世界最高能量E^+E^ - Collider LEP已于1989年开始运营。在1995年完成了Z共振的非常成功的物理计划后，LEP在1996年开始了Energy升级程序LEP2，超过了碰撞能量，足以使W Boson成对产生W骨头。 1997年，LEP碰撞能量增加到183 GEV，并在1998年进一步提高到189 0EV。我们一直在发挥领导作用的蛋白石实验已成功地收集了这个新能源区域的数据。为了充分利用这些数据，我们致力于了解高能以高能量的探测器性能，检测器的精确校准，改进的物理分析技术的发展，以获得测量和搜索的敏感性，我们还追求了许多新的物理主题。1。已经收集了大约4000个W对事件。精确测量了生产横截面，总W宽度和衰减分支比率。 W质量的准确测量以及Z玻色子的精确结果，为标准模型的关键测试提供了信息。基于W对事件的增加数据样本，W质量测定的精度已得到很大改善。2。对标准模型过程（例如费米对生产，Z对生产，单W生产和一般四效最终状态）进行了系统的研究。发现标准模型在这个较高的能源区域效果很好。3。希格斯玻色子的质量是标准模型的关键要素，但尚未被发现，比大约91 GEV.4重。进行了超对称颗粒的搜索，并获得了该理论中参数的限制。