1996 Fiscal Year Final Research Report Summary
Productions of XI-hypernuclei・atoms and Transitions to double-LAMBDA atates
| Project/Area Number |
07640418
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
素粒子・核・宇宙線
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| Research Institution | Tsuru university |
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Principal Investigator |
YAMAMOTO Yasuo Tsuru University literature professor, 教授 (80124866)
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| Project Period (FY) |
1995 – 1996
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| Keywords | strangeness / double-LAMBDA hypernucleus / (K^-, K^+) reaction / XI^- absorption / double-LAMBDA compound nucleus / pi^- mesonic decay |
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| Research Abstract |
Recently, much interest is taken in double-strangeness states (XI hypernuclei, XI^- atoms and double-LAMBDA hypernuclei etc.) and interactions of elementary processes of LAMBDALAMBDA and XIN.Tne aim of our study was to investigate productions and structures of double-strangeness states, and transition processes due to strong interactions. In the KEK-E176 experiment with use of the hybrid technique of emulsion and counter, they observed the many XI^--stop events in emulsion after (K^-, K^+) reactions. Then, there were found one event of producing a double-LAMBDA nucleus and three events of simultaneous emissions of two single-LAMBDA hypernuclei. These events are considered that the XI^- trapped in an atomic orbit is absorbed into the nucleus, and the two LAMBDA produced by the XI^-p-LAMBDALAMBDA conversion stick to the nucleus.
On the other hand, we proposed the new idea of observing double-LAMBDA hypernuclei more efficiently : The XI^- particle produced predominantly in the quasi-free r
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egion is absorbed into the target nucleus through the slowdown process due to the rescattering with a nucleon, and the XI^-p-LAMBDALAMBDA conversion in the nucleus leads to the double-LAMBDA sticking intermediate state (double-LAMBDA compound nucleus) and the following frag-mentation into double-LAMBDA products. Then, produced double-LAMBDA hypernuclei can be confirmed by detecting successive pions from their weak decays.
On the basis of the eikonal approximation we estimated the amount of double-LAMBDA sticking via tile slowdown process of quasi-freely produced XI particle. The fragmentation of the formed doublel-LAMBDA cormpound nucleus, treated with a statistical model, leads to several particular double-LAMBDA hypernuclei with high prob-abilities. In the case of the ^9Be target, especially, the number of breaking-up channels is small, and the production probability of ^5_<BDALAMBDA> is distinctively large. This feature gives a suitable and feasible condition of experiment with this target. Thus, the scenario of producing more double-LAMBDA hypernuclei through the slowdown of quasi-free XI^- was confirmed on the quantitative basis. Now a new experiment (E906) is in progress at BNL-AGS to detect double-LAMBDA hypernuclei by observing characteristic pi^- mesonic decays at (K^-, K^+) reaction points. The major results of out study were reflected in their proposal. Less
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Research Products
(12 results)
