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The one-phonon mixed-symmetry $2^+$ of $^{132}$Te is of high interest due to the specific structure of this nucleus, with two valence-proton particles and two valence-neutron holes with respect to the doubly-magic nucleus $^{132}$Sn. In recent experiments, the second excited $2^+$ state has been assigned as the one-phonon mixed-symmetry $2^+$ state [1], due to the high B(M1) transition strength between this state and the $2_1^+$ state, which is the proton-neutron symmetric counterpart of the mixed-symmetry state. However, the obtained value is highly uncertain and extraordinarily large with 5.4(3.5)$\, \mu_N^2$, mainly due to the $50\, \%$ uncertainty in the reference value of its decay branching ratio to the $2_1^+$ and $0_1^+$ state [2].
By populating the $2_2^+$ state in a two-neutron transfer reaction $^{130}$Te($^{18}$O,$^{16}$O)$^{132}$Te at IFIN-HH in Romania, it was now possible to obtain a more precise value for the B(M1) transition strength. This was achieved by determining the lifetime after performing a lineshape analysis of the deexcitation $\gamma$-rays using the Doppler-shift attenuation method.
[1] M. Danchev et al., Phys. Rev. C 84 (2011) 061306(R)
[2] R. O. Hughes et al., Phys. Rev. C 71 (2005) 044311
