Hadron-Induced Multifragmentation

For light-ion-induced reactions in the bombarding energy regime 1–10 GeV, dramatic changes occur for inclusive observables associated with highly excited heavy residues.1 For example, the excitation functions for IMF production (IMF: 3 ≤ Z ≥ 15) increase by more than two orders of magnitude over this energy range-while the N-N total scattering cross section changes only gradually. This has been interpreted in terms of large deposition energies in the residue, giving rise to multifragmentation events. Subsequent 4π studies2 have verified this interpretation and further shown that the most highly excited residues are produced with very low velocities (v/c ∼ 0.01). This latter fact suggests the importance of baryonic resonances in the excitation process; the former demonstrates that light-ion-induced reactions create hot, multifragmenting systems that can be observed in the laboratory with minimal kinematic distortion.