Analysis of the width of the momentum distribution of He fragments produced in relativistic 16O + Em collisions

The increase of the width of the momentum distribution of He fragments with decreasing He-multiplicity in relativistic 16O fragmentation at 2 GeV/N to 200 GeV/N is analyzed. The result shows that with decreasing He-multiplicity the surface-excitation energy of the projectile-spectator increases, for the reason of the increase of the width of the momentum distribution. Although the incident energy changes the projectile-spectator obtains the same excitation energy under the same geometric conditions. This gives the limiting fragmentation behavior of the He multiplicity distribution