Transverse momenta of helium fragments in gold fragmentation at 10.6 GeV/nucleon

The transverse momentum (p(t)) distributions of helium fragments from gold fragmentation on different nuclei of nuclear emulsion have been measured and a clear increase of average p(t) with target mass is seen. The p(t) distributions can be parameterized by a sum of three exponential functions of the form similar to exp(-p(t)(2)/B-i). The differences in p(t) distributions in interactions on different targets can be explained by different contributions of the three exponential functions. These contributions depend on the projectile breakup in the collision, and for a given degree of the projectile breakup do not depend on the target mass.