Chinese Physics C > 2013, Vol. 37 > Issue(2): 024102 DOI: 10.1088/1674-1137/37/2/024102

Symmetry energy from neutron-rich fragments in heavy-ion collisions, and its dependence on incident energy, and impact parameters

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The yields of fragments produced in the ⁶⁰Ni+ ¹²C reactions at 80 A and 140 A MeV, and with maximum impact parameters of 1.5, 2 and 7.3 fm at 80 A MeV are calculated by the statistical abrasion-ablation model. The yields of fragments are analyzed by the isobaric yield ratio (IYR) method to extract the coefficient of symmetry energy to temperature ( a _sym/ T). The incident energy is found to influence a _sym/ Tvery little. It's found that a _sym/ Tof fragments with the same neutron-excess I= N-Zincreases when A increases, while a _sym/ Tof isobars decreases when A increases. The a _sym/ Tof prefragments is rather smaller than that of the final fragments, and the a _sym/ Tof fragments in small impact parameters is smaller than that of the larger impact parameters, which both indicate that a _sym/ Tdecreases when the temperature increases. The choice of the reference IYRs is found to have influence on the extracted a _sym/ Tof fragments, especially on the results of the more neutron-rich fragments. The surface-symmetry energy coefficient ( b _s/ T) and the volume-symmetry energy coefficient ( b _v/ T) are also extracted, and the b _s/ b _vis found to coincide with the theoretical results.

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MA Chun-Wang, SONG Heng-Li, PU Jie, ZHANG Tong-Lin, ZHANG Sha, WANG Shan-Shan, ZHAO Xin-Li and CHEN Li. Symmetry energy from neutron-rich fragments in heavy-ion collisions, and its dependence on incident energy, and impact parameters[J]. Chinese Physics C, 2013, 37(2): 024102. doi: 10.1088/1674-1137/37/2/024102

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Received: 2012-03-27
Revised: 1900-01-01

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沈阳化工大学材料科学与工程学院沈阳 110142

Symmetry energy from neutron-rich fragments in heavy-ion collisions, and its dependence on incident energy, and impact parameters

Corresponding author:MA Chun-Wang,

Received Date:2012-03-27
Accepted Date:1900-01-01
Available Online:2013-02-05

Abstract:The yields of fragments produced in the⁶⁰Ni+¹²C reactions at 80 A and 140 A MeV, and with maximum impact parameters of 1.5, 2 and 7.3 fm at 80 A MeV are calculated by the statistical abrasion-ablation model. The yields of fragments are analyzed by the isobaric yield ratio (IYR) method to extract the coefficient of symmetry energy to temperature (a_sym/T). The incident energy is found to influencea_sym/Tvery little. It's found thata_sym/Tof fragments with the same neutron-excess I=N-Zincreases when A increases, whilea_sym/Tof isobars decreases when A increases. Thea_sym/Tof prefragments is rather smaller than that of the final fragments, and thea_sym/Tof fragments in small impact parameters is smaller than that of the larger impact parameters, which both indicate thata_sym/Tdecreases when the temperature increases. The choice of the reference IYRs is found to have influence on the extracteda_sym/Tof fragments, especially on the results of the more neutron-rich fragments. The surface-symmetry energy coefficient (b_s/T) and the volume-symmetry energy coefficient (b_v/T) are also extracted, and theb_s/b_vis found to coincide with the theoretical results.