Abstract
Background: Two new states are recently observed a few MeV above the Hoyle state (the second state in ). Their characteristics are only briefly discussed in theory and are still mysterious.
Purpose: I give for the first time a comprehensive understanding of the structures of the states by analyzing their wave functions and discuss relationship with the Hoyle state, similarities, and differences between the states.
Method: I extend a microscopic -cluster model called the Tohsaki-Horiuchi-Schuck-Röpke (THSR) wave function so as to incorporate the asymmetric configuration explicitly. The so-called -constraint method to effectively eliminate spurious continuum components is also used.
Results: The state is shown to have a very large squared overlap with a single configuration of the extended THSR wave function in an orthogonal space to the Hoyle state as well as to the ground state. The state has a maximal squared overlap with a single extended THSR wave function with an extremely prolately deformed shape.
Conclusions: The state appears as a family of the Hoyle state to have a higher nodal structure in the internal motions of the clusters, due to the orthogonalization to the Hoyle state. The state dominantly has a linear-chain structure, where the clusters move freely in a nonlocalized way, like a one-dimensional gas of the clusters.
1 More- Received 12 July 2016
DOI:https://doi.org/10.1103/PhysRevC.94.024344
©2016 American Physical Society