Speaker
Prof.
Hiroyuki Fujioka
(Tokyo Institute of Technology)
Description
Double-$\Lambda$ hypernuclei have been investigated for more than half a century, and several double-$\Lambda$ hypernuclei have been found in nuclear emulsion. While they were produced by $\Xi^-$ capture in light nuclei, Kumagai-Fuse and Akaishi proposed a possibility to produce a double-$\Lambda$ hypernucleus as a decay product of a $\Xi$ hypernucleus [1]. According to their calculation, the branching ratio of ${}^7_{\Xi}\mathrm{H}\to {}^5_{\Lambda\Lambda}\mathrm{H}+2n$ is as large as 90%, because many-body decay such as $^4_{\Lambda}\mathrm{H}+\Lambda+2n$ is disfavored due to its small $Q$-value.
The existence of the $^{7}_{\Xi}\mathrm{H}$ bound state is predicted in a more recent calculation [2].
In this contribution, we will discuss a possible experiment for $^5_{\Lambda\Lambda}\mathrm{H}$ production
using the $^7\mathrm{Li}(K^-,K^+){}^7_{\Xi}\mathrm{H}$ reaction, followed by the $^7_{\Xi}\mathrm{H}\to {}^5_{\Lambda\Lambda}\mathrm{H}+2n$ decay.
A simultaneous study of $\Xi$ hypernuclei and Double-$\Lambda$ hypernuclei will give an insight into $\Xi N$-$\Lambda\Lambda$ mixing and conversion, which is one of the most important features in the $S=-2$ sector.
References
1. Kumagai-Fuse and Y. Akaishi, Phys. Rev. C 54, R24 (1996).
2. E. Hiyama, Y. Yamamoto, T. Motoba, T. A. Rijken, and M. Kamimura, Phys. Rev. C 78, 054316 (2008).
Primary author
Prof.
Hiroyuki Fujioka
(Tokyo Institute of Technology)
Co-authors
Prof.
Emiko Hiyama
(Kyushu University and RIKEN Nishina Center)
Prof.
Tomokazu Fukuda
(RIKEN Nishina Center)
