Abstract
Background: Isoscalar monopole transition has been suggested as a key observable to search for exotic cluster states. Recently, excited states with strong isoscalar monopole transition strengths were experimentally reported in , but their structures were not revealed because of the lack of theoretical analysis.
Purpose: We study the structure of the excited states of populated by isoscalar monopole transition from the ground state, and identify their cluster configurations.
Method: The states of and their isoscalar monopole transition strengths from the ground state are calculated with antisymmetrized molecular dynamics combined with the generator coordinate method using the Gogny D1S interaction.
Results: The calculated isoscalar monopole strength function shows reasonable agreement with experiment and is consistent with other theoretical calculations. The structures of the excited states with pronounced isoscalar monopole transitions are analyzed. It is found that the , and states have mixed nature of mean-field and cluster, and that the state is dominated by a cluster configuration. In addition, it is predicted that states appear around 23 MeV.
Conclusions: The excited states which appear as the prominent peaks in the calculated strength function are associated with , and cluster states.
- Received 23 February 2015
- Revised 2 April 2015
DOI:https://doi.org/10.1103/PhysRevC.91.061302
©2015 American Physical Society