Experimental Study on Quark-Gluon-Plasma at BNL

BNL 夸克-胶子-等离子体实验研究

基本信息

批准号：
03044034
负责人：
HOMMA Saburo
金额：
$ 5.76万
依托单位：
Institute for Nuclear Study, 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：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

项目摘要

The experiment with high-intensity 14.5 AGeV Si-beams and the first-round experiment with 11 AGeV Au-beams have been carried out by the Japan-US international collaboration in high energy heavy ion collisions at the AGS, Brookhaven National Laboratory, USA.Primary goals of the experiment are (1) to study the two-particle correlations for pions and Kaons, and (2) to measure the rarely-produced hadrons (i.e. K-and anti-proton) with good statistics using the experimental system with a magnetic spectrometer as a central device.Space-time evolution of nucleus-nucleus collisions could be investigated through two-particle correlation measurement. Trial of measuring K-and anti-proton were made before, but low statistics prevented us to deduce any conclusions for their productions.In order to achieve the goals, we built a special trigger system by which particle identification in the trigger-level was made possible. Stringent event selection capability made it possible to run with high-intensity beams.Data analyses of two particle correlations are in progress, and preliminary result shows that source size measuremed by pions is significantly smaller than that measured by Kaons.Anti-proton yield was consisten with the model calculation with no anti-protons absorption in nuclear matter, which strongly contradicts to the naive expectation.With the completion of AGS-Booster, experiments with heavy ions up to Au became possible. We can expect a better condition to study unclear matter at extreme conditions with heavy ions. The first Au beam was available in May, 1992, and we had a prelminary short run. Purity of Au beam was better than 99%. Measurements of transverse and forward energy flow were made. Measurement of particle spectra at backward angle with spectrometer were also tried.Data analysis going on, and the construction of a new spectrometer which covers the forward angular region is in progress.

高强度14.5 AGeV硅束流实验和11 AGeV金束流首轮实验由日美高能重离子对撞国际合作组织在美国布鲁克海文国家实验室AGS开展。该实验的主要目标是（1）研究π介子和Kaons的双粒子相关性，以及（2）测量很少产生的强子（即强子）。以磁谱仪为中心装置的实验系统具有良好的统计性。通过双粒子相关测量可以研究核-核碰撞的时空演化。之前曾尝试过测量K-和反质子，但由于统计数据太少，我们无法对其产品得出任何结论。为了实现目标，我们建立了一个特殊的触发系统，通过该系统在触发级进行粒子识别可能的。严格的事件选择能力使得高强度束流运行成为可能。两个粒子关联的数据分析正在进行中，初步结果表明，π介子测量的源尺寸明显小于Kaons测量的源尺寸。反质子产额一致模型计算中没有核物质中的反质子吸收，这与天真的预期强烈矛盾。随着AGS-Booster的完成，重离子至Au的实验成为可能。我们可以期待更好的条件来用重离子研究极端条件下的不明物质。第一个金光束于 1992 年 5 月上市，我们进行了初步的短期生产。 Au束的纯度优于99%。进行了横向和前向能量流的测量。还尝试了用光谱仪测量后角的粒子光谱。数据分析正在进行中，并且正在建造覆盖前角区域的新型光谱仪。