Correlations between energy and mass partition in the damped reactionHo165+

Abstract

Data from a kinematical coincidence experiment on the damped reaction ' Ho+' Ge at 8.5MeV/nucleon have been reanalyzed. Although the new analysis confirms the presence of some correlations between the excitation-energy division and the mass asymmetry, the magnitude of these correlations is found to be significantly smaller than that previously reported. Proton-neutron symmetry of the mechanism of heat generation through nucleon exchange is revealed and a possible acceptor-donor asymmetry of this mechanism is discussed.

Angular Momentum Sharing in Dissipative Collisions

“…The observed correlation between the total number of emitted nucleons and the net mass transfer indicates a non-equilibrium excitation energy partition between the reaction products, with an excess of excitation being deposited in the fragment which gains nucleons. Similar conclusions had been drawn by other authors [12][13][14][15][16], but remained quite controversial. Although the existence of such correlations is compatible, by itself, with a nucleon exchange picture, the fact that they are largely independent of the degree of inelasticity [11,15] is difficult to understand within the present versions of the stochastic nucleon exchange model and deserves new investigation.…”

Direct Experimental Evidence of Nonequilibrium Energy Sharing in Dissipative Collisions

“…However, with increasing dissipation, the larger and larger number of independent nucleon exchanges should almost wash out the correlation. Toke et al [10] emphasized the surprising constancy of the donor-acceptor intrinsic asymmetry η which they deduced from a re-analysis of the data of Ref. [4].…”

“…The determination of the microscopic mechanism of energy dissipation and energy partition between the reaction partners of a dissipative collision has been a controversial subject of debate in the past years [1][2][3][4][5][6][7][8][9][10][11][12] (for a review see [13]). The excitation energy sharing presents an evolution with the inelasticity of the reaction: in quasi-elastic events the two reaction partners reseparate with almost equal excitation energies, but with increasing dissipation there is a trend towards equilibrium partition (i.e.…”

“…These experimental findings can be explained by models [14] which describe the evolution of many macroscopic observables by means of stochastic exchanges of single nucleons between the interacting nuclei. More refined experiments [4,7,10] claimed that the excitation energy division is correlated with the net mass transfer, with an excess of excitation being deposited in the fragment which gains nucleons. Moreover, the strength of this experimental correlation seems to be largely independent of the degree of inelasticity [10] and this latter result seems difficult to understand within a stochastic nucleon exchange picture.…”

Energy partition in near-barrier strongly damped collisionsNi58+

“…Subsequent reexamination [15][16][17] of some of the experimental data obtained in the kinematical coincidence experiments [6][7][8] at a few MeV per nucleon above the barrier has shown that the reported correlations result to a large extent from deficiencies in the data analysis procedure employed.…”