Study of Doubly Strangeness Nuclei

本研究的目的是利用圆柱形探测器系统(CDS)和BNL/AGS上1.8GeV/c的高强度K束(LO**6/秒)寻找双波长超核。到目前为止，只有两个候选双波长超核。我们的方法是通过(K-，K+)反应中S=-2的类化合物态产生双波长超核，并用CDS连续观察衰变的两个介子来探测它们。我们预计统计数据比以前高两个数量级。我们在去年完成了COS，测试实验表明CDS和束线光谱仪系统在BNL/AGS上表现良好。今年我们积累了从9月到11月的数据。初步分析表明，在双粒子谱中，相关动量区有许多事件。我们希望在改进CDS的动量分辨后，能够识别出双波长超核。我们的数据包含了关于S=-2核系统的信息，例如具有比以前更高的统计量的级联超核、H粒子，所以我们也将对这些有趣的主题给出新的结果。

The aim of this study is to search for double-lambda hypernuclei by using the Cylindrical Detector System (CDS) and a high intensity K-beam (lO**6/sec) with 1.8 GeV/c at BNL/AGS.There have been only two candidates for double-lambda hypernuclei so far studied. Our method is to produce double-lambda hypernuclei through a compound-like state with S=-2 in the (K-, K+) reaction and to detect them by observing sucessively decaying two pions with CDS.We expect higher statistics by two orders of magnitudes than before.We have completed COS in the last year and the test experiment showed a good performance of CDS as well as the beam-line spectrometer system at BNL/AGS.In this year we have accumulated the data from September through November . A preliminary anaysis shows that there are many events for relevant momentum regions in two-pions spectrum. We hope we can identify double -lambda hypernuclei after the improvement of the momentum resolution of CDS.Our data contains information concerning S=-2 nucler systems such as cascade hypernuclei, H-particle with higher statistics than before, so that we will also give new results about those interesting topics.