Shell evolution approaching the N=20 island of inversion: structure of 26Na
Abstract
The levels in 26Na with single particle character have been observed for the first time using the d(25Na,p gamma) reaction at 5 MeV/nucleon. The measured excitation energies and the deduced spectroscopic factors are in good overall agreement with (0+1) hbar-omega shell model calculations performed in a complete spsdfp basis and incorporating a reduction in the N=20 gap. Notably, the 1p3/2 neutron configuration was found to play an enhanced role in the structure of the low-lying negative parity states in 26Na, compared to the isotone 28Al. Thus, the lowering of the 1p3/2 orbital relative to the 0f7/2 occurring in the neighbouring Z=10 and 12 nuclei -- 25,27Ne and 27,29Mg -- is seen also to occur at Z=11 and further strengthens the constraints on the modelling of the transition into the island of inversion.
Keywords
Cite
@article{arxiv.1508.01757,
title = {Shell evolution approaching the N=20 island of inversion: structure of 26Na},
author = {G. L. Wilson and W. N. Catford and N. A. Orr and C. Aa. Diget and A. Matta and G. Hackman and S. J. Williams and I. C. Celik and N. L. Achouri and H. Al Falou and R. Ashley and R. A. E. Austin and G. C. Ball and J. C. Blackmon and A. J. Boston and H. C. Boston and S. M. Brown and D. S. Cross and M. Djongolov and T. E. Drake and U. Hager and S. P. Fox and B. R. Fulton and N. Galinski and A. B. Garnsworthy and D. Jamieson and R. Kanungo and K. G. Leach and J. N. Orce and C. J. Pearson and M. Porter-Peden and F. Sarazin and E. C. Simpson and S. Sjue and D. Smalley and C. Sumithrarachchi and C. E. Svensson and S. Triambak and C. Unsworth and R. Wadsworth},
journal= {arXiv preprint arXiv:1508.01757},
year = {2016}
}
Comments
6 figures