Production of helium projectile fragment in 84Kr-emulsion collisions at 1.7 A GeV

Multiplicity, projected angular and transverse momentum distributions of helium projectile fragment (HPF) produced from 1.7 A GeV 84Kr induced different type of emulsion targets (H, CNO and AgBr) interactions are studied. It is found that the distributions of HPF from 84Kr–H, CNO, AgBr and emulsion interactions can be well explained by two Gaussian distributions. These imply the existence of two distinct emission sources (cold and hot source) of HPF in 84Kr–H, CNO, AgBr and emulsion interactions. The dominant source is the cold one (projectile spectator source) with lower temperature and the other is hot one (projectile participant source) with higher temperature. The temperature parameters of cold and hot source are obtained from pt2 distribution fitting using two Rayleigh distribution, which is independent of the target size within experimental errors.

► Multiplicity distribution can be well represented by two Gaussian distributions.
► Projected angular distributions can be well fitted by two Gaussian distributions.
► Transverse momentum distribution can be well explained by two Gaussian distributions.
► The temperature of emission sources is obtained from pt2 distribution.
► The temperature parameter is independent of the target size.