Energy dependence of peripheral reactions induced by heavy ions

Abstract

Collisions of 16 0 ions on targets of 94 2 197A 208Pb, and 232 111. . d • .d r, u, are 1nvest1gate at mc1 ent energies of 140 and 315 MeV, and compared to published data on peripheral collisions at 33.6 GeV. At 140 MeV, the isotope-production cross sections resemble the ground-state Q-value systematics characteristic of a partially-equilibrated, di-nuclear system formed in deeply-inelastic scattering. The yields are independent of shell and pairing effects in the target and residual nuclei. These Q-value systematics fail at 315 MeV, where the relative element yields are similar to those at 33.6 GeV. A theory of projectile fragmentation accounts for. .

Features of direct cluster stripping in primary fragments from quasielastic20Ne-induced reactions

“…We know that the neutronrich fragments are formed with increased relative intensity in collisions with neutron-rich targets [-7]. Their relative strengths are also somewhat increased when compared to collisions on the same target at very high energy (2 GeV/nucleon) [4]. This suggests that at lower bombarding energies neutron-pick-up from the target occurs with a certain probability.…”

S-matrix spin and parity decoherence and damping of coherent nuclear rotation: quantum chaos in dissipative heavy-ion collisions?

“…This suggests the classical picture of a rotating molecule with rotation period 2π~/α and angular velocity ω = α/~, so that α =~ω. Accordingly, (4.16) takes the form of the angular distribution of the classically rotating dinuclear system having an average life-time~/Γ and angular velocity ω [34,35]. Equation (4.16) has been successfully applied to analyse numerous experimental angular distributions in DHIC (see, for example, [34][35][36][37]).…”

Pre-equilibrium alpha emission accompanying deep-inelastic16O+58Ni collisions

“…We write 1/zhs = hs hs 1/'r, + 1/'c+ . (24) Here, 1/zhts=2/z is the total particle decay rate (into the continuum) and 1/'c] S is the rate of internal decay.…”

“…A partly direct, or pre-equilibrium character of the reaction, however, is revealed in the angular correlation measurements, presented in Section 5. This section * The reaction 2~ C0~) has been studied recently at 20 MeV/N [24] contains the data on in-plane and out-of-plane correlations, the ~ multiplicities and the angle-dependent shape of the c~ spectra. A general discussion is given in Section 6.…”