Münster 2002 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 47: Heavy Ions VI
HK 47.6: Vortrag
Donnerstag, 14. März 2002, 17:45–18:00, E
Isoscaling in Light-Ion Induced Reactions and its Statistical Interpretation — •Alexandre Botvina1, Oleg Lozhkin2, and Wolfgang Trautmann1 — 1GSI, Planckstrasse 1, D-64291 Darmstadt — 2KRI, St.Petersburg, Russia
Isotopic effects observed in fragmentation reactions induced by protons, deutrons and alpha-particles of incident energies between 0.66 and 15.3 GeV on 112-Sn and 124-Sn targets are discussed. The exponential scaling of the yield ratios with the third component of the fragment isospin (N-Z)/2 is observed in all reactions, with the scaling parameters that depend on the incident energy. Breakup temperatures for these reactions are deduced from double ratios of isotopic yields and tested for their relation with the isoscaling parameters. The observed isoscaling can be understood as a consequence of a statistical origin of the emitted fragments in these reactions. The Statistical Multifragmentation Model analysis shows that the exponent describing the isoscaling behavior is proportional to the strength of the symmetry term of the fragment binding energy. A symmetry-term coefficient around 22.5 MeV for fragments at low density breakup stage is deduced from the experimental data, that is slightly weaker than for isolated nuclei.