Study on Meson Spectroscopy-Search for Exotic States

欧洲核研究组织、IHEP （Protuino）和KEK的合作项目促进了1987年在KEK举行的第二次强子光谱仪国际会议的使用。GAMS是一种总吸收类型的总吸收的尼克名称，它可以检测到伽马射线从一个中性介子状态衰减。GAMS实验开始作为1978年欧洲核研究组织和IHEP之间的国际合作，在第六次CERN-IHEP实验的框架内。GAMS方案涵盖了在欧洲核研究组织IHEP和GAMS-4000（NA 12/2）的两个电磁光谱仪的研究活动。合作活动得到以下机构的支持;法国LAPP、比利时IISN、比萨大学意大利、美国LANL、USSR IHEP和日本KEK。GAMS项目的主线是对新的中性光介质共振的系统搜索，包括外来国家（球球、混合体等）和其他国家。 ... More 新的罕见中性衰退模式，以已知的梅森共振。这些中性介质在多个衰退中产生--伽马射线在两个排他性过程中产生; pi^-p电荷交换反应和Hadrons的中央集合。在欧洲核研究组织的450 GeV/c生产了100和400 GeV/c之间的鸽子和原型，在IHEP使用了30和40 GeV/c生产了70 GeV/c的鸽子。GAMS已经观察到了几个新的国家，其中G（1590）/f_0（1590）是突出的。这是一个尺度的状态，它将进入埃塔、埃塔和4pi，它将被认为是一个球的候选人。M （1405）是在etapi^0 decay mode中发现的一个重要对象。Its quantum numbers are J^<PC>=1^\-+&gt; which are qq exotic.在同一方向上的活动也曾在KEK进行过。梅森州包括exotics是通过使用电荷和伽马光谱仪搜索的， Benkei在KEK的12 GeV质子同步加速器。GAMS合作形式，现在是由三个机构执行的一个综合实验方案。1988-1990年期间，GAMS合作执行机器时间在6月至8月在欧洲核研究组织运行，11月至11月在IHEP每年运行。数据摘要磁带已被传送到每个机构。分析是不正确的。同时，数据获取系统已通过使用VME系统进行改进，以便按顺序过滤事件，并最大限度地提高GAMS-4000和GAMS-4pi的获取时间。GAMS-2000已升级到GAMS-4pi，以增加固体角度覆盖面，并在氢目标和宽角度热量计系统周围添加防护系统。大型漂移室已安装用于检测充电粒子，GAMS项目计划继续到1993年收集数据。Less（低）

The collaboration project of the GAMS experiment among CERN, IHEP (Protuino) and KEK took shape promoting the occasion of the 2nd International Conference on Hadron Spectroscopy held at KEK in 1987. GAMS is a nickname of the electromagnetic calorimeter hodoscope of a total absorption type which detects gamma rays decaying from a neutral meson state. The GAMS experiment started as an international collaboration between CERN and IHEP in 1978 in the framework of the 6th joint CERN-IHEP experiment. The GAMS program covers the research activity that is taking place around two Electromagnetic Spectrometers which are GAMS-2000/4pi at IHEP and GAMS-4000 (NA12/2) at CERN. The collaboration activities are supported by the following institutions ; LAPP of France, IISN of Belgium, Pisa Univ. of Italy, LANL of USA, IHEP of USSR and KEK of Japan.The main line of the GAMS project is a systematic search for new neutral light meson resonances including exotic states (glueballs, hybrids and others) and … More for new rare neutral decay modes of known meson resonances. These neutral mesons which decay into multiーgamma rays are produced in two exclusive processes ; pi^-p charge exchange reactions and central collisions of hadrons. Pions and protons ranging between 100 and 400 GeV/c produced by the 450 GeV SPS at CERN and pions between 30 and 40 GeV/c produced by the 70 GeV PS at IHEP have been used in the reactions. GAMS has already observed several new states, among which G(1590)/f_0(1590) is prominent. It is a scalar state which decays into etaeta, etaeta' and 4pi and is considered as a candidate of a glueball. M (1405) is an important object which has been found in etapi^0 decay mode. Its quantum numbers are J^<PC>=1^<-+> which are qq exotic. Activities in the same direction have been also pursued at KEK. Meson states including exotics are searched for by using the charge and gamma spectrometer, Benkei at the 12 GeV Proton Synchrotron at KEK. The GAMS collaboration forms, now, a combined experimental program performed by the three institutions.During 1988-1990, the GAMS collaboration executed machine time runs in June-August at CERN and in NovemberーDecember at IHEP in each year. The data summary tapes have been delivered to each institutions. Analyse are under way. Meanwhile, the data acquisition system has been improved by using a VME system in order to filter events and to maximize acquisition time in both GAMS-4000 and GAMS-4pi. GAMS-2000 is upgraded to GAMS-4pi augmenting the solid angle coverage by adding the guard system around the hydrogen target and the wide angle calorimeter system. Large drift chambers have been installed for detecting charged particles.The GAMS project is scheduled to continue to accumulate data till 1993. Less