| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 2006: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2005: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2004: ¥900,000 (Direct Cost: ¥900,000)
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| Research Abstract |
One of fundamental problems in the strangeness nuclear physics is to reveal the entire picture of strong interactions among octet baryons. SU(3)-invariant interaction models give useful guidance toward such an aim. Then, it is decisively important to establish S=-2 interactions, because features predicted by various interaction models are remarkably different from each other in S=-2 channels. Especially distinctive are their ΞN sectors. Th. A. Rijken and Y. Yamamoto have proposed the new interaction models ESC04 (a, b, c, d), in which two-meson and meson-pair exchanges are taken into account and no effective boson is included. The features of ESC04 models are very different from those of the OBE models especially in S=-2 channels. Among ESC04 models, ESC04d is distinctively important, because the derived Ξ-nucleus attractions are comparable to the experimental indication owing to the strong attraction in the T=0 3^S_1 state. The attraction in this state is so strong that peculiar Ξ bound states can be produced even in s-and light p-shell systems. In our studies, we have demonstrated the features of S=-2 systems derived from ESC04d on the basis of the G-matrix approach. For comparison, we have shown also the results for Nijmegen hard-core model D (NHC-D). In the past, NHC-D has been used popularly for S=-2 interactions, because this model is compatible with strong ΛΛ attraction indicated by the old data of double-∧ hypernuclei, and gives an attractive values of Ξ potential energy in nuclear matter. These features of NHC-D are owing to its specific feature that only the scalar singlet is taken into account. Another important feature of ESC04d in the S=-2 channel is that the meson-pair exchange terms give rise to the strong ΞN-ΛΛ coupling interaction. We have investigated the Ξ-mixing effect into some double-Λ hypernuclei on the basis of ESC04 models.
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