Mach-like emission from nucleon scattering in proton-nucleus reactions

Abstract

The fast-stage nucleon emission of proton-nucleus (pA) reactions from 300A MeV to 1.8A GeV has been investigated by the quantum molecular dynamics model. It is found that the sideward angular spectrum of nucleon emission presents an interesting Mach-like structure at the early stage of the collision (tens of fm/c). The sideward angular peak value varies from about 45• to near 73• , depending on the bombarding energy. Nucleons emitted from the vicinity of the sideward peak tend to have a fixed momentum value about 0.5 GeV/c, independent of the bombarding energy as well as the impact parameter. Additionally, the sideward angular peak value is almost independent of equation of state, indicating that binary collision at the early fast stage in the intermediate energy pA reaction plays an important role for emergence of Mach-like emission.

Rotational Property of 249 Cm in Particle-Triaxial-Rotor Model

“…In the present work, we take κ and µ as those quite close to the standard value, [32] κ = 0.0545, µ = 0.4252. For the energy gap parameter, considering the reduction of the pairing strength in very heavy nuclei as given quite recently, [15] we take ∆ = 0.30 MeV. To improve the agreement between the calculated energy spectrum and the experimental one, a Coriolis attenuation factor ξ = 0.99 is introduced here.…”

“…Since the percentage of the 6d 5/2 1/2 configuration in the single particle level is slightly larger than those of others, such a band can be assigned as the [620] 1 2 + band, just as that assigned in Refs. [1][2]15].…”