Isolated mixed-symmetry 2+state of the radioactive neutron-rich nuclide 132Te

AbstraktAbstract

The M1 transition strengths between excited 2+ states of the neutron-rich, radioactive nuclide 132Te was studied through direct lifetime measurements using the Doppler-shift attenuation method in a two-neutron transfer reaction on a 130Te target. An unambiguous identification of the lowest-lying mixed-symmetry 2+ state was achieved on the basis of the large B(M 1; 2+2 -* 2+1 ) = 0.18(2) mu 2N transition strength. Results are compared to the shell model, and the analysis of both data and calculations unambiguously identifies the second-excited 2+ state of 132Te as the one-quadrupole phonon mixed-symmetry state of this isotope. A lowering of the energy and B(M 1; 2+ms -* 2+1 ) strength within the N = 80 isotones toward the Z = 50 shell closure is observed, which occurs along with the lowering of the E2 collectivity approaching the magic proton shell.

The M1 transition strengths between excited 2+ states of the neutron-rich, radioactive nuclide 132Te was studied through direct lifetime measurements using the Doppler-shift attenuation method in a two-neutron transfer reaction on a 130Te target. An unambiguous identification of the lowest-lying mixed-symmetry 2+ state was achieved on the basis of the large B(M 1; 2+2 -* 2+1 ) = 0.18(2) mu 2N transition strength. Results are compared to the shell model, and the analysis of both data and calculations unambiguously identifies the second-excited 2+ state of 132Te as the one-quadrupole phonon mixed-symmetry state of this isotope. A lowering of the energy and B(M 1; 2+ms -* 2+1 ) strength within the N = 80 isotones toward the Z = 50 shell closure is observed, which occurs along with the lowering of the E2 collectivity approaching the magic proton shell.