Search for Duble Lambda Hypernuclei

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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.