Three-dimensional isospin projection and T=0–T=1 mixing in Tz=0 nuclei

Investigate whether mixing between the states |T=1,T_z=0⟩ and |T=0,T_z=0⟩ explains the suppressed B(E2;2_1^+→0_1^+) transition rates of the T_z=0 members of the A=70, 74, and 78 isospin triplets by performing three-dimensional isospin projection.

Background

The calculations find that the measured B(E2;2_1+→0_1+) values for the T_z=0 members of the A=70, 74, and 78 triplets are suppressed relative to the values predicted by the isospin-invariant Skyrme density-functional calculations. The authors identify mixing between the T=1,T_z=0 and T=0,T_z=0 states as a possible explanation for this suppression.

The approximate isospin projection used in the study cannot resolve this mixing. A three-dimensional isospin projection would be required to project the T=0 and T=1 components of the T_z=0 nuclei and determine whether their mixing accounts for the anomalous transition strengths.

References

A plausible explanation for the suppressed $B(E2,2_1+ \rightarrow 0_1+)$ rates in the $T_z=0$ members of the three studied isospin triplets is the mixing between the states $|T=1,T_z=0\rangle$ and $|T=0,T_z=0\rangle$. However, this possibility could not be investigated in the present work, as it would require three-dimensional isospin projection.

— Isospin-invariant Skyrme density functional investigation of quadrupole deformations in the isospin triplets of $\bf{A=70, 74}$ and $\bf{78}$  (2610.25936 - Tak et al., 19 Oct 2026) in Section III, Results and discussion