The electric quadrupole moment Q for the ground state of 17B was determined by the β-NMR method applied to spin-polarized projectile fragments. From the measured quadrupole coupling constant, |eqQ/h(17 in Mg)| = 137.4±4.5 kHz, for 17B in a Mg single crystal stopper the Q moment was deduced as |Q(17B)| = 38.6±1.5 mb. As was the case in the previous 15B result, the obtained Q moment is very close to that for the N = 8 isotope 13B, in sharp contrast to the results of conventional shell-model calculations using constant effective charges. Comparison of the shell-model calculations indicates substantial reduction of the E2 effective charges for isotopes with large (N-Z)/A ratios. The results were well accounted for in terms of (N-Z)/A dependent E2 polarization charges as predicted by Bohr and Mottelson and by incorporating the decoupling feature of loosely bound particles.
|Number of pages||9|
|Journal||Physical Review C - Nuclear Physics|
|Publication status||Published - Jun 2003|
ASJC Scopus subject areas
- Nuclear and High Energy Physics