Mass-separated 187Ta in a high-spin isomeric state has been produced for the first time by multi-nucleon transfer reactions, employing an argon gas stopping cell and laser ionisation. Internal gamma rays revealed a 7.3 s isomer at 1778 keV, which decays through a rotational band with perturbations associated with the approach to a prolate-oblate shape transition. Model calculations show less influence from triaxiality compared to heavier elements in the same mass region. The isomer decay reduced E2 hindrance factor of 27 supports the interpretation that axial symmetry is approximately conserved.
@article{arxiv.2011.04284,
title = {Properties of 187Ta revealed through isomeric decay},
author = {P. M. Walker and Y. Hirayama and G. J. Lane and H. Watanabe and G. D. Dracoulis and M. Ahmed and M. Brunet and T. Hashimoto and S. Ishizawa and F. G. Kondev and Yu. A. Litvinov and H. Miyatake and J. Y. Moon and M. Mukai and T. Niwase and J. H. Park and Zs. Podolyak and M. Rosenbusch and P. Schury and M. Wada and X. Y. Watanabe and W. Y. Liang and F. R. Xu},
journal= {arXiv preprint arXiv:2011.04284},
year = {2020}
}