| Autor: |
Bello Garrote, F.L., Lopez-Martens, A., Larsen, A.C., Deloncle, I., Péru, S., Zeiser, F., Greenlees, P.T., Kheswa, B.V., Auranen, K., Bleuel, D.L., Cox, D.M., Crespo Campo, L., Giacoppo, F., Görgen, A., Grahn, T., Guttormsen, M., Hagen, T.W., Harkness-Brennan, L., Hauschild, K., Henning, G., Herzberg, R.D., Julin, R., Juutinen, S., Laplace, T.A., Leino, M., Midtbø, J.E., Modamio, V., Pakarinen, J., Papadakis, P., Partanen, J., Renstrøm, T., Rezynkina, K., Sandzelius, M., Sarén, J., Scholey, C., Siem, S., Sorri, J., Stolze, S., Uusitalo, J. |
| Jazyk: |
angličtina |
| Rok vydání: |
2022 |
| Zdroj: |
Physics Letters |
| Popis: |
We present the first experimental evidence of the scissors mode in the superheavy nucleus $^{254}$No produced in the $^{208}$Pb($^{48}$Ca, 2nγ))$^{254}$No reaction. The spectrum of γ rays emitted by the excited $^{254}$No nuclei shows an enhanced γ-ray yield for transition energies of ≈2.5 MeV. By measuring the linear polarization properties of the emitted γ rays, we confirm that the transitions in the enhancement region are predominantly of magnetic-dipole character, characteristic for the scissors mode. To further characterize the enhanced γ-ray yield, simulations of the electromagnetic decay of $^{254}$No were performed. The observed enhancement is reproduced by including an M1 component in the γ strength function with total strength B(M1↑)=11.8(19)μN2. This is in good agreement with the integrated M1 strength from sum-rule estimates and new calculations within the quasi-particle random-phase approximation presented here. Our results provide a stringent test of phenomenological formulae for the scissors mode currently used in stellar nucleosynthesis calculations. We find that those formulae are not satisfactory, and we recommend using sum-rule estimates assuming a rigid-body moment of inertia instead for describing the scissors mode in superheavy nuclei. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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