Data Analysis of High-Energy Nucleus-Nucleus Collision Experiment NA44

1.利用动量聚焦谱仪，在CERN-SPS加速器上积累了450-GeV质子-核和200-GeV/核子硫-核碰撞的大量原始数据。对于硫束，我们研制了一种新型的气体切伦科夫计数器。该计数器工作成功，时间分辨率达到了35ps，是世界上最好的。广岛大学物理系对数据进行了分析。在这一分析中，特别强调精确的粒子识别以及高统计量。分析确定了以下量：(1)出现在末态的各种强子的单能谱。(2)pi^*pi^*和kappa^**kappa^*的两粒子关联函数。单峰光谱可以用横向质量M_T的指数函数来描述，粒子越轻，斜率越大。光谱还表明，任何反常增强的存在都是根本不存在的，有些作者曾声称在小动量转移时存在这种增强。强子源的大小是由观测到的两粒子关联函数确定的。对于p+Pd碰撞，介子源的大小从2fm增加到了S+pb碰撞的5fm。介子源的大小大约是克子源大小的两倍，这意味着比Points更早冻结克子。在S+铅相互作用中，Kappa^+和Kappa^-源大小没有明显差异。

1. By means of a momentum focussing spectrometer, a large amount of raw data on 450-GeV proton-nucleus and 200-GeV/nucleon sulphur-nucleus collisions have been accumulated at the CERN-SPS accelerator.2. For the sulphur beam, we developed a new type of gas Cherenkov counter. The counter worked successfully and achieved a time resolution of 35 ps, which is the best in the world.3. The data have been analyzed at the Department of Physics, Hiroshima University. In this analysis, special emphasis is put on precise particle identification as well as on high statistics. The analysis determined the following quantities:(1) Singles spectra for various hadrons appearing in the final state.(2) Two-particle correlation functions for pi^*pi^* and KAPPA^*KAPPA^*.4. Singles spectra can be described by an exponential function of the transverse mass M_T and the lighter the particle, the steeper the slope.5. The spectra also show that any anomalous enhancement, the existence of which has been claimed at small momentum transfers by some authors, does not exist at all.6. The hadron source sizes are determined from the observed two-particle correlation functions. The pion source size increases from 2 fm for p+Pd collisions to 5 fm for S+Pb collisions.7. The pion source size is about twice as large as the kaon source size, implying an earlier freeze-out of kaons than pions.8. No substantial difference is seen between the KAPPA^+ and KAPPA^- source sizes in S+Pb interaction.