Orbital dispersion and wavefunction mapping in inclusive break-up experiments

Abstract

Inclusive break-up cross sections of the reactions 12C (6Li, a)X and 2~ (6Li, a)X at 26 MeV/amu, observed for the emission of break-up fragment into the forward hemisphere, are analysed in view of the information about the internal momentum distribution of the projectile. The longitudinal momentum distribution of the fragments in the projectile rest-frame is found to reflect the internal momentum distribution of the clusters whereas the transverse distribution is affected by the projectile-target interaction.

Reaction mechanism of 6Li scattering at 600 MeV

“…But in both cases the σ 0 derived from heavier targets (Au and Pb) are smaller than the ones derived from lighter targets (Al, C, Ni, Zr). Also our σ 0 are significantly higher than the value found by Srivastava et al [7] for 12 C target and an incident energy of 26A MeV, which is only σ 0 =28.6 MeV/c. According to Srivastava et al [7] this low value for σ 0 indicates a change of the breakup reaction mode from transfer to fast abrasion-ablation processes.…”

“…Also our σ 0 are significantly higher than the value found by Srivastava et al [7] for 12 C target and an incident energy of 26A MeV, which is only σ 0 =28.6 MeV/c. According to Srivastava et al [7] this low value for σ 0 indicates a change of the breakup reaction mode from transfer to fast abrasion-ablation processes. When comparing with the σ 0 of 86 MeV/c found for an incident energy of 2.1A GeV and the value found by Srivastava et al it is plausible that our value, measured at an energy of 100A MeV, lies in between both values.…”

“…A low energy tail can be observed which has been interpreted at 156 MeV as a physical background coming from precompound and compound nuclear reactions [29]. As mentioned above the longitudinal momentum distribution has been found to reflect the internal momentum distribution of the clusters within the projectile whereas the transverse momentum distribution has been found to be affected by the projectile-target interaction [7,8]. Since the mentioned investigations have been done either with heavier projectiles and fragments or by using a much lower energy, our own data shall be presented here based on 100A MeV 6 Li projectiles.…”

“…This could mean that the momentum distribution in case of the first three targets does not only reflect the internal Fermi motion of the clusters within the projectile but shows also an additional broadening by interaction with the nucleus. This effect would not be visible in the case of the low energy scattering presented in [7] where only Coulomb scattering takes place.…”

“…This implies a velocity distribution of the spectator-particles which results from a superposition of the beam-velocity with the internal motion of the fragments inside the projectile. It has been found that the longitudinal momentum distribution directly reflects the internal momentum distribution of the clusters within the projectile whereas the transverse momentum distribution is affected by the projectile-target interaction [7,8].…”