Search for Duble Lambda Hypernuclei

1.我们在美国布鲁克海文国家实验室的AGS加速器上准备了鉴定双-Λ超核，特别是^4<_<ΛΛ>H>的实验。然而，由于预算问题，所有的固定目标质子实验都被推迟了。在研制过程中，研制了一种新型阴极读出室。另外，有几个理论小组一直在尝试计算^4<_<ΛΛ>H>质量，这对提取λ - λ相互作用非常重要，并等待实验结果。本文首次在KEK的PS加速器上，利用（π^-,K^+）反应在^<10>B靶上产生了富中子超光速粒子。这项研究对于理解超核中的Λ-Σ耦合以及中子星等致密核物质中的超子混合具有重要意义。我们已经成功地观察到^<10><_ΛLi>的束缚态，这将导致产生更多的奇异超核，如^6<_ΛH>。我们还通过双电荷交换反应获得了Λ， Σ^-和Λ的准自由生成数据，这将有助于提取Σ^-核相互作用。

1.We have prepared the experiment to identify double-Λ hypernuclei, in particular ^4<_<ΛΛ>H>, at AGS accelerator of Brookhaven National Laboratory in US. However all the experiments by using protons on fixed target have been postponed due to budgetary problem. During the preparation period we have developed a new type of cathode readout chamber. In addition several theoretical groups have been trying to calculate the ^4<_<ΛΛ>H> mass, which is very important to extract lambda-lambda interaction, and await the experimental result.2.We have carried out the experiment to produce a neutron-rich hypercleus for the first time at PS accelerator of KEK by using (π^-,K^+) reaction on ^<10>B target. This study is quite important in order to understand the Λ-Σ coupling in hypernuclei as well as hyperon mixing in dense nuclear matter like neutron stars. We have successfully observed bound states of ^<10><_ΛLi>, which will lead to the production of more exotic hypernuclei such as ^6<_ΛH>. We also took data on the quasi-free production of Λ, Σ^-as well as Λ via double charge-exchange reaction, which will help to extract the Σ^--nucleus interction.