$B(E2;2_1^{+}\to 0_1^{+})$ anomaly in ${}^{166}$Os

Abstract

Recently, the very small $B(E2;2_1^{+}\to 0_1^{+})$ value was found in ${}^{166}$Os, which is 7(4) W.u. \textbf{and} much smaller than the values of adjacent nuclei ${}^{168,170}$Os, 74(13) W.u. and 97(9) W.u.. With the help of a new technique ``SU(3) analysis" and a new explanatory framework of the B(E2) anomaly, it was found that, the $B(E2;2_1^{+}\to 0_1^{+})$ anomaly really can exist. In this paper, we discuss the $B(E2;2_1^{+}\to 0_1^{+})$ anomaly in ${}^{166}$Os for the first time. Four results are used to fit the experimental data in ${}^{166,168,170}$Os successfully. This implies that the level-crossing or level-anticrossing explanation is more reasonable.