Systematic analyses on Hydrogen isotopes by using an extended AMD approach

It is a very challenging problem to make an extremely neutron-excess system which corresponds to the neutron star. Very recently, an experimental evidence of $^7$H was reported as an enhancement of the cross section above the t+$n$+$n$+$n$+$n$ threshold [1]. Its neutron ratio to the proton is the largest value of six. It is very interesting to investigate pair correlations between the nucleons and the cluster-like correlation of triton in such the almost neutron matter like nuclei only with one proton. Recently, we propose a new extended AMD approach [2]. In this approach, AMD combined with the generator coordinate method is extended with the idea of the stochastic variational method (SVM). We call this new approach AMD triple-S (Superposition of Selected Snapshots) [2]. By using AMD triple-S, we will give the calculated results and discussions for H-isotopes with the core-nucleus plus the valence neutrons model, and discuss the nucleon correlations in the extremely neutron-rich nuclei. Work done in collaboration with Naoyuki Itagaki, Niigata University. \newline \newline [1] A.A. Korsheninnikov $et$ $al.$, Phys. Rev. Lett. {\bf90}, 082501 (2003). \newline [2] N. Itagaki, A. Kobayakawa and S. Aoyama, Phys. Rev. {\bf C68}, 054302 (2003).