TY  - JOUR
AU  - Stahl, C. et al
AU  - Gadea, A.
PY  - 2015
DA  - 2015//
TI  - Population of the 2(ms)(+) mixed-symmetry state of Ba-140 with the alpha-transfer reaction
T2  - Phys. Rev. C
JO  - Physical Review C
SP  - 044324
EP  - 7pp
VL  - 92
IS  - 4
PB  - Amer Physical Soc
AB  - Background: Identification of proton-neutron mixed-symmetric one-quadrupole phonon excitations (the 2(ms)(+) states) of atomic nuclei provides information on the isovector part of the residual nucleon-nucleon interaction. It was predicted that the 2(ms)(+) state of particular nuclei close to the U(5) limit of the interacting boson model, in particular Ba-140, should be considerably populated by alpha-transfer reactions [C. E. Alonso et al., Phys. Rev. C 78, 017301 (2008)]. Purpose: We aim at the identification of the 2(ms)(+) mixed-symmetry state (MSS) of radioactive Ba-140 and investigate its population by the alpha-transfer reaction as a suitable tool to selectively populate MSSs and as a potential new signature for its mixed-symmetric character. Method: A gamma-ray spectroscopy experiment was performed in inverse kinematics in order to populate the 2(ms)(+) state of Ba-140 by alpha-transfer from a C-nat target on Xe-136 beam ions. The population of the candidate for the 2(ms)(+) state of Ba-140 was measured relative to the population of the 2(1)(+) state. Results: The candidate for the 2(ms)(+) state of Ba-140 was populated by a transfer three times weaker than predicted. Another 2(+) state that can be ruled out as the MSS was in turn as strongly populated by the a transfer as predicted for the MSS. Conclusions: The relative population of 2(+) states by alpha-transfer cannot serve as a new signature for MSSs, since other 2(+) states are also strongly populated. Nevertheless, the substantial population of the MSS candidate of Ba-140 by alpha transfer qualifies this type of reaction as suitable tool to excite MSSs and study their electromagnetic decay properties.
SN  - 0556-2813
UR  - https://doi.org/10.1103/PhysRevC.92.044324
DO  - 10.1103/PhysRevC.92.044324
LA  - English
N1  - WOS:000363524900001
ID  - Stahl+Gadea2015
ER  -