skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Single and double {pi}{sup -}/{pi}{sup +} ratios in heavy-ion reactions as probes of the high-density behavior of the nuclear symmetry energy

Abstract

Based on the isospin- and momentum-dependent hadronic transport model IBUU04, effects of the nuclear symmetry energy on the single and double {pi}{sup -}/{pi}{sup +} ratios in central reactions of {sup 132}Sn+{sup 124}Sn and {sup 112}Sn+{sup 112}Sn at a beam energy of 400 MeV/nucleon are studied. It is found that around the Coulomb peak of the single {pi}{sup -}/{pi}{sup +} ratio the double {pi}{sup -}/{pi}{sup +} ratio taken from the two isotopic reactions retains about the same sensitivity to the density dependence of nuclear symmetry energy. Because the double {pi}{sup -}/{pi}{sup +} ratio can significantly reduce the systematic errors, it is thus a more effective probe for the high-density behavior of the nuclear symmetry energy.

Authors:
 [1];  [2];  [3];  [4];  [2];  [1]
  1. Institute of Modern Physics, Chinese Academy of Science, Lanzhou 730000 (China)
  2. (China)
  3. Department of Chemistry and Physics, P.O. Box 419, Arkansas State University, State University, Arkansas 72467-0419 (United States)
  4. Institute of Theoretical Physics, Shanghai Jiao Tong University, Shanghai 200240 (China)
Publication Date:
OSTI Identifier:
20771350
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 73; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevC.73.034603; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; DENSITY; HEAVY ION REACTIONS; ISOSPIN; MEV RANGE; PARTICLE PRODUCTION; PIONS MINUS; PIONS PLUS; SYMMETRY; TIN 112; TIN 124; TIN 132; TRANSPORT THEORY

Citation Formats

Yong Gaochan, Graduate School, Chinese Academy of Science, Beijing 100039, Li Baoan, Chen Liewen, Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000, and Zuo Wei. Single and double {pi}{sup -}/{pi}{sup +} ratios in heavy-ion reactions as probes of the high-density behavior of the nuclear symmetry energy. United States: N. p., 2006. Web. doi:10.1103/PhysRevC.73.034603.
Yong Gaochan, Graduate School, Chinese Academy of Science, Beijing 100039, Li Baoan, Chen Liewen, Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000, & Zuo Wei. Single and double {pi}{sup -}/{pi}{sup +} ratios in heavy-ion reactions as probes of the high-density behavior of the nuclear symmetry energy. United States. doi:10.1103/PhysRevC.73.034603.
Yong Gaochan, Graduate School, Chinese Academy of Science, Beijing 100039, Li Baoan, Chen Liewen, Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000, and Zuo Wei. Wed . "Single and double {pi}{sup -}/{pi}{sup +} ratios in heavy-ion reactions as probes of the high-density behavior of the nuclear symmetry energy". United States. doi:10.1103/PhysRevC.73.034603.
@article{osti_20771350,
title = {Single and double {pi}{sup -}/{pi}{sup +} ratios in heavy-ion reactions as probes of the high-density behavior of the nuclear symmetry energy},
author = {Yong Gaochan and Graduate School, Chinese Academy of Science, Beijing 100039 and Li Baoan and Chen Liewen and Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000 and Zuo Wei},
abstractNote = {Based on the isospin- and momentum-dependent hadronic transport model IBUU04, effects of the nuclear symmetry energy on the single and double {pi}{sup -}/{pi}{sup +} ratios in central reactions of {sup 132}Sn+{sup 124}Sn and {sup 112}Sn+{sup 112}Sn at a beam energy of 400 MeV/nucleon are studied. It is found that around the Coulomb peak of the single {pi}{sup -}/{pi}{sup +} ratio the double {pi}{sup -}/{pi}{sup +} ratio taken from the two isotopic reactions retains about the same sensitivity to the density dependence of nuclear symmetry energy. Because the double {pi}{sup -}/{pi}{sup +} ratio can significantly reduce the systematic errors, it is thus a more effective probe for the high-density behavior of the nuclear symmetry energy.},
doi = {10.1103/PhysRevC.73.034603},
journal = {Physical Review. C, Nuclear Physics},
number = 3,
volume = 73,
place = {United States},
year = {Wed Mar 15 00:00:00 EST 2006},
month = {Wed Mar 15 00:00:00 EST 2006}
}
  • The double neutron-proton differential transverse flow taken from two reaction systems using different isotopes of the same element is studied at incident beam energies of 400 and 800 MeV/nucleon within the framework of an isospin- and momentum-dependent hadronic transport model IBUU04. The double differential flow is found to retain about the same sensitivity to the density dependence of the nuclear symmetry energy as the single differential flow in the more neutron-rich reaction. Because the double differential flow reduces significantly both the systematic errors and the influence of the Coulomb force, it is thus more effective probe for the high-density behaviormore » of the nuclear symmetry energy.« less
  • The relative isobaric yields of fragments produced in a series of heavy-ion-induced multifragmentation reactions have been analyzed in the framework of a modified Fisher model, primarily to determine the ratio of the symmetry energy coefficient to the temperature, a{sub sym}/T, as a function of fragment mass A. The extracted values increase from 5 to approx16 as A increases from 9 to 37. These values have been compared to the results of calculations using the antisymmetrized molecular dynamics (AMD) model together with the statistical decay code gemini. The calculated ratios are in good agreement with those extracted from the experiment. Inmore » contrast, the values extracted from the ratios of the primary isobars from the AMD model calculation are approx4 to 5 and show little variation with A. This observation indicates that the value of the symmetry energy coefficient derived from final fragment observables may be significantly different than the actual value at the time of fragment formation. The experimentally observed pairing effect is also studied within the same simulations. The Coulomb coefficient is also discussed.« less
  • The isobaric yield ratios of the fragments produced in the neutron-rich {sup 48}Ca and {sup 64}Ni projectile fragmentation are analyzed in the framework of a modified Fisher model. The correlations between the isobaric yield ratios (R) and the energy coefficients in the Weiszaecker-Beth semiclassical mass formula (the symmetry-energy term a{sub sym}, the Coulomb-energy term a{sub c}, and the pairing-energy term a{sub p}) and the difference between the chemical potentials of the neutron and proton ({mu}{sub n}-{mu}{sub p}) are investigated. Simple correlations between ({mu}{sub n}-{mu}{sub p})/T, a{sub c}/T, a{sub sym}/T, and a{sub p}/T (where T is the temperature), and lnR aremore » obtained. It is suggested that ({mu}{sub n}-{mu}{sub p})/T, a{sub c}/T, a{sub sym}/T, and a{sub p}/T of neutron-rich nuclei can be extracted using isobaric yield ratios for heavy-ion collisions at intermediate energies.« less
  • In the framework of the isospin-dependent Boltzmann-Uehling-Uhlenbeck transport model, the effect of the momentum dependence of the nuclear symmetry potential on the {pi}{sup -}/{pi}{sup +} ratio in the neutron-rich reaction {sup 132}Sn +{sup 124}Sn at a beam energy of 400 MeV/nucleon is studied. We find that the momentum dependence of the nuclear symmetry potential affects the compressed density of colliding nuclei, the numbers of produced {pi}{sup -} and {pi}{sup +}, as well as the value of the {pi}{sup -}/{pi}{sup +} ratio. The momentum-dependent nuclear symmetry potential increases the compressed density of colliding nuclei, the number of produced resonances {Delta}(1232), N{supmore » *}(1440), {pi}{sup -}, and {pi}{sup +}, as well as the value of the {pi}{sup -}/{pi}{sup +} ratio.« less