Abstract
The pairing energy () of fragments, which is assumed to have a finite temperature in heavy-ion collisions, is obtained using an isobaric yield ratio method in the framework of a modified Fisher model. The fragments in the measured and simulated MeV and reactions have been adopted to perform the analysis. The results show that the ratio of the pairing-energy coefficient to the temperature () is not significantly influenced by the reaction system, but depends on the neutron excess of the fragment. For most fragments, falls in the range of . Assuming MeV for the intermediate-mass fragments, MeV is suggested, which is much smaller than the value in the semiclassical mass formula. For a neutron-rich fragment, may disappear. The results are confirmed by the calculated of some isobars using the self-consistent finite-temperature relativistic Hartree-Bogoliubov model with the effective interaction PC-PK1 and the Gogny-pairing interaction D1S. The calculated depends on in the form of and goes to zero fast with temperatures at around MeV. The results are useful for improving the secondary decay simulation for primary fragments in the heavy-ion collisions.
- Received 8 April 2016
DOI:https://doi.org/10.1103/PhysRevC.94.024615
©2016 American Physical Society