Volume 81, Number 4, February 2008
Article Number 42002
Number of page(s) 6
Section Nuclear Physics
Published online 24 January 2008
EPL, 81 (2008) 42002
DOI: 10.1209/0295-5075/81/42002

$\mth{\eta}$-mesic nuclei in relativistic mean-field theory

C. Y. Song1, X. H. Zhong2, L. Li1 and P. Z. Ning1

1  Department of Physics, Nankai University - Tianjin 300071, China
2  Institute of High Energy Physics, Chinese Academy of Sciences - Beijing 100039, China

received 13 August 2007; accepted in final form 21 December 2007; published February 2008
published online 24 January 2008

With the $\eta $-nucleon ($\eta N$) interaction Lagrangian deduced from chiral perturbation theory, we study the possible $\eta $-mesic nuclei in the framework of relativistic mean-field theory. The $\eta $ single-particle energies are sensitive to the $\eta N$ scattering length, and increase monotonically with the nucleon number A. If the scattering length is in the range of  $a^{\eta N}$ = 0.75 - 1.05 fm and the imaginary potential V0 ~ 15 MeV, some discrete states of  $_{\eta}^{12} {\rm C}$, $_{\eta}^{16}{\rm O}$ and  $_{\eta }^{20} {\rm Ne}$ should be identified in experiments. However, when the scattering length  $a^{\eta N}$ < 0.5 fm, or the imaginary potential V0 > 30 MeV, no discrete $\eta $-meson bound states could be observed in experiments.

21.10.Pc - Single-particle levels and strength functions.
21.30.Fe - Forces in hadronic systems and effective interactions.

© EPLA 2008