Isospin mixing between low-lying states of the odd-odd N = Z nucleus 54Co.

Isospin mixing of the recently discovered doublet of 4(+) states with isospin quantum numbers T = 0 and T = 1 in 54Co is analyzed. It is shown that the measured E2/M1 multipole mixing ratios can be used to estimate the isospin mixing of these states. Combining the new experimental data with results of a shell model calculation, the amount of isospin mixing is found to be approximately 0.2%.

Proton-neutron mixed-symmetry 3(+)(ms) state in 94Mo

We identify a Jpi = 3(+)(ms) state in 94Mo. This identification is based on six M1 and E2 strengths and is the first identification of a 3(+)(ms) state from B(M1) and B(E2) values. The transition strengths were determined from the measurement of Doppler shifts, branching ratios, and E2/M1 mixing ratios, obtained from gammagamma directional correlations following the 91Zr(alpha,n) reaction and the beta(+) decay of (94)Tc(m). The interacting boson model agrees with the observations, which prove the 2(+) mixed-symmetry states to be a building block in nuclear structure.