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arXiv · nucl-ex/0409026

Isotopic Scaling and the Symmetry Energy in Spectator Fragmentation

Abstract

Isotopic effects in the fragmentation of excited target residues following collisions of $^{12}$C on $^{112,124}$Sn at incident energies of 300 and 600 MeV per nucleon were studied with the INDRA 4$π$ detector. The measured yield ratios for light particles and fragments with atomic number $Z \leq$ 5 obey the exponential law of isotopic scaling. The deduced scaling parameters decrease strongly with increasing centrality to values smaller than 50% of those obtained for the peripheral event groups. Symmetry term coefficients, deduced from these data within the statistical description of isotopic scaling, are near $γ=$ 25 MeV for peripheral and $γ<$ 15 MeV for central collisions.

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The INDRA, ALADIN Collaborations, :, A. Le Fèvre, G. Auger, M. L. Begemann-Blaich, N. Bellaize, R. Bittiger, F. Bocage, B. Borderie, R. Bougault, B. Bouriquet, J. L. Charvet, A. Chbihi, R. Dayras, D. Durand, J. D. Frankland, E. Galichet, D. Gourio, D. Guinet, S. Hudan, G. Immé, P. Lautesse, F. Lavaud, R. Legrain, O. Lopez, J. Łukasik, U. Lynen, W. F. J. Müller, L. Nalpas, H. Orth, E. Plagnol, G. Raciti, E. Rosato, A. Saija, C. Schwarz, W. Seidel, C. Sfienti, B. Tamain, W. Trautmann, A. Trzciński, K. Turzó, E. Vient, M. Vigilante, C. Volant, B. Zwiegliński, A. S. Botvina. 2005-04-06. Isotopic Scaling and the Symmetry Energy in Spectator Fragmentation. https://doi.org/10.1103/physrevlett.94.162701

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