2018 Impact factor 2.481
Hadrons and Nuclei
Eur. Phys. J. A 16, 21-26 (2003)
DOI: 10.1140/epja/i2002-10083-y

$\mth{\Lambda\Lambda\tx{-}\Xi}$ $\chem{N}$ coupling effects in light hypernuclei

Khin Swe Myint1, S. Shinmura2 and Y. Akaishi3

1  Department of Physics, Mandalay University, Mandalay, Union of Myanmar
2  Department of Information Science, Gifu University, Gifu 501-1193, Japan
3  Institute of Particle and Nuclear Studies, KEK, Tsukuba 305-0801, Japan

akaishi@post.ket.jp

(Received: 17 July 2002 / Revised version: 24 September 2002 / Published online: 17 January 2003)

Abstract
The significance of $\Lambda\Lambda$- $\Xi$ $\chem{N}$ coupling in double- $\Lambda$ hypernuclei has been studied. The Pauli suppression effect due to this coupling in $^6_{\Lambda\Lambda}$ $\chem{He}$ has been found to be 0.43 MeV for the coupling strength of the NSC97e potential. This indicates that the free-space $\Lambda\Lambda$ interaction is stronger by an about $5^{\circ}$ phase shift than that deduced from the empirical data of $^6_{\Lambda\Lambda}$ $\chem{He}$ without including the Pauli suppression effect. In $^5_{\Lambda\Lambda}$ $\chem{He}$ and $^5_{\Lambda\Lambda}$ $\chem{H}$, an attractive term arising from the $\Lambda\Lambda$- $\Xi$ $\chem{N}$ conversion is enhanced by the formation of an alpha-particle in the intermediate $\Xi$ states. According to this enhancement, we have found that the $\Lambda\Lambda$ binding energy ( $\Delta B_{\Lambda\Lambda}$) of $^5_{\Lambda\Lambda}$ $\chem{He}$ is about 0.27 MeV larger than that of $^6_{\Lambda\Lambda}$ $\chem{He}$ for the NSC97e coupling strength. This finding deviates from the general picture that the heavier is the core nucleus, the larger is  $\Delta B_{\Lambda\Lambda}$.

PACS
21.80.+a - Hypernuclei.
21.10.Dr - Binding energies and masses.
21.45.+v - Few-body systems.

© Società Italiana di Fisica, Springer-Verlag 2003