Suo-chang Jin | Searcharxiv

arXiv2025

$B(E2;2^{+}_{1}\rightarrow0^{+}_{1})$ anomaly in $^{166}$Os

Recently, the very small $B(E2;2_{1}^{+}\rightarrow0_{1}^{+})$ 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 $B(E2;2_{1}^{+}\rightarrow0_{1}^{+})$ anomaly really can exist. In this paper, we discuss the $B(E2;2_{1}^{+}\rightarrow0_{1}^{+})$ 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.

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arXiv2025

Level-anticrossing in B(E2) anomaly (I)

Recently, a new mechanism for explaining the B(E2) anomaly was given by F. Pan \emph{et al.} (PRC, 110, 054324, 2024), which is realized in the parameter region from the SU(3) symmetry limit to the O(6) symmetry limit, and seems to be not related to the SU(3) symmetry. However, through SU(3) analysis, a new technique proposed recently, we found that it is not so. The new mechanism is related to level-anticrossing phenomenon, which is related to level-crossing phenomenon in the SU(3) symmetry limit. By incorporating previous ideas, we have a more general explanatory framework for the B(E2) anomaly, which is important for understanding some higher-order interactions in the interacting boson model. Through analysis, it is shown that level-anticrossing in this mechanism mainly results from the third-order interaction $[\hat{L}\times \hat{Q}_χ \times \hat{L}]^{(0)}$. Finally, the B(E2) anomaly in $^{170}$Os is also discussed within this general framework.

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