“基本粒子”的实验研究近况

这篇总结性文章论述了最近四、五年来“基本粒子”实验研究的发展情况。全文着重讨论了强相互作用粒子的发展情况,关于弱相互作用问题则谈得不多。其主要原因是:在强相互作用粒子方面,近年来实验上发现了大量的粒子共振态,以致使粒子总数由30种剧增到100种左右,而且,有关的理论方面也相应地取得了成功的发展——由强相互作用对称性提出的SU(3)分类方案。正是这些新发展,使得对所谓基本粒子(至少对强相互作用粒子来说)是有结构的、是可分的看法在近年来更加明确了。本文总结和讨论了最近四、五年来较重要的七组实验——四组关于强相互作用问题,三组关于弱相互作用问题,并且,集中地讨论了强相互作用粒子在最近几年来的发展情况,1960年前后的统计对比以及粒子分类的物理意义等,这些为讨论SU(3)和Regge轨迹分类方案准备了有利的物理条件。在讨论SU(3)和Regge轨迹分类方案时,本文只着重讨论了这两个方案(特别是SU(3))的物理背景和设想、方案的数学基础、理论结果及其与实验的比较。通过和实验比较,Regge轨迹方案就显出了远不如SU(3)方案,这个事实和Regge极理论所出现的严重问题(参看第二章第3节)当然是分不开的。希望通过这篇文章能向读者介绍“基本粒子”在这几年中的发展概况,在现阶段解决或摸清了那些问题,以及今后实验工作的可能方向。

RECENT DEVELOPMENT IN THE EXPERIMENTAL STUDY OF “ELEMENTARY PARTICLES”

This paper intends to give a comprehensive survey of the development in the experimental study of "elementary particles" during the last four or five years. However, the most part of the paper has been devoted to the strongly interacting particles, bringing into discussion only a few problems concerning the weak interaction. The main reason for doing so is this: It is in the area of the strongly interacting particles that there has been in these years a rapid and large accumulation of newly discovered facts, that is, the resonant states of particles, quickly bringing the total number of particles from about 30 to about 100; moreover, in the corresponding theoretical aspect, there is also up to now a more or less successful development, that is, the SU(3) classification scheme as proposed from the symmetry of strong interaction. Simply because of these new developments, we are now more than ever certain that the so-called elementary particles are not elementary but composite, i.e. having internal structure (at least as far as the strongly interacting particles are concerned). This point has been discussed in some detail in the "Introduction". The paper then summari2es and discusses seven groups of experiments which have been performed in the last four or five years and are considered as more important in the field of "elementary particles", four groups being concerned with the strong interaction while three groups with the weak interaction. After this, discussion has been concentrated on the recent development of the strongly interacting particles, on the status of statistics before and after 1960, and on the physical meaning of the particle classification, etc. It is hoped that this will provide a physical background for discussing the classification schemes of SU(3) and the Regge trajectories. Finally, in discussing the two classification schemes, particularly the SU(3) scheme, effort has been made to explain with as much clarity as possible the physical background and the conjecture made, the mathematical basis, the theoretical results, and comparison with experiment. Comparison with experiment shows that the Regge trajectory scheme is not at all as satisfactory as the SU(3) scheme, this being naturally related with the serious difficulty as revealed by experiment (cf. Section II.3) of the theory of Regge poles. It is hoped that this paper may present a general picture of the recent development of "elementary particles", probably showing what problems have become clear and what still have not, and may possibly indicate the direction of future experimental research.