Investigation of transverse momentum distributions for fragments produced in reactions of ${}^{197}\mathrm{Au}$ and ${}^{208}\mathrm{Pb}$ projectiles with different targets in the energy range from 1.0 to 158 GeV/nucleon

We have analyzed fragmentation processes of ${}^{197}\mathrm{Au}$ and ${}^{208}\mathrm{Pb}$ projectiles in reactions with targets ranging from ${\mathrm{CH}}_2$ to Pb at projectile energies between 1.0 and 158 GeV/nucleon. For these experiments we used stacks consisting of foils of the plastic nuclear track detector material ${\mathrm{C}\mathrm{R}-39(\mathrm{C}}_{12}{\mathrm{H}}_{18}{\mathrm{O}}_7).$ This detector material allows us to measure the charges and trajectories of relativistic particles with charges above a detection threshold $Z_t.$ In this paper we analyze target and projectile energy dependences of transverse momentum distributions for projectile fragments produced in different fragmentation processes such as spallation, fission, and multifragmentation. Furthermore, for multifragmentation processes multiplicity dependences of the transverse momenta were studied. We found that besides the statistically distributed Fermi momenta of the nucleons, Coulomb repulsion may significantly contribute to the transverse momenta of the fragment nuclei. For heavy target nuclei, contributions caused by the repulsion of the incoming projectile nucleus and also by the outgoing fragment nucleus have been observed. For fission-type reactions and for multifragmentation reactions, in which more than one heavy fragment is produced in an interaction, the mutual repulsion between the fragments contributes to the measured transverse momenta.