Momentum transfer in the fragmentation of copper by 400-GeV protons

Abstract

Mean momenta transferred to products of the fragmentation of copper by 400-GeV protons have been determined by the thick-target thick-catcher technique. Comparison with data for incident protons and heavy ions indicates that the limiting fragmentation region has been reached and supports a simple relationship between momentum and energy transfers in peripheral reactions which had been proposed previously.

Onset of Damping in Energetic Heavy-Ion Interactions

“…The asymptotic approach of j8|| for a particular product to a lower limit at very high energies is a characteristic feature of a peripheral process. 6 As rapidities decrease, momentum transfers initially rise in general agreement with Eq. (1).…”

“…(1) with k = l and AE values determined by measurements at higher energies. 6 While the dashed curve at 84 MeV/u has the same shape as the experimental data, it falls ~ 30% below the points.…”

“…These new data provide an important connection between the intermediate energy region and the extensive data available for this target at higher energies 6 -up to 400 GeV. They permit comparisons with predictions 6 and observations 1 of upper limits on momentum transfer in target fragmentation processes and allow evaluation of the need for novel processes such as solitons 2 to account for changes in reaction dynamics.…”

“…6 A target stack consisted of a 47 mg/cm 2 Cu foil with 7 mg/cm 2 Mylar catchers on the upstream and downstream sides. An additional Mylar was included as a blank.…”

“…In the limit of full momentum transfer, the prefragment is the compound nucleus moving with 0" = £ CN# Derivation of 0" and 7 from measured mean ranges employed the same general procedure as had been used previously. 6 It was modified, however, to include a Maxwellian distribution of recoil energies corresponding to 7, the same distribution as was assumed by Lund etal. 1 We also explored a broader distribution as well as a unique value of 7.…”