Nuclear fragmentation in interactions of $3.7A\mathrm{GeV}$ ${}^{24}\mathrm{Mg}$ projectiles with emulsion targets

The process of nuclear fragmentation in interactions of $3.7A\mathrm{GeV}$ ${}^{24}\mathrm{Mg}$ nuclei with the different target nuclei in a nuclear emulsion have been investigated. The total charge distributions of nuclear fragments are well described by the predictions of the extended Glauber model. The multiplicity and charge distributions of fragments with $Z⩾5$ in quasinucleon target events are found to agree satisfactorily with the calculations of the bond percolation model. The fragmentation of the projectile nucleus depends strongly on the target mass. The probability of interactions without any projectile fragments with charges $Z>2$ is zero for a hydrogen target, but increases by increasing the mass of the target. The disruption of a projectile nucleus is more severe in interactions with the heavy target nuclei than with the light ones. The topology for the nuclear fragmentation channels in interactions of the different projectiles with the different components of emulsion nuclei in the energy range $3.7–200A\mathrm{GeV}$ was analyzed. The average multiplicities and the relative rates of nuclear fragmentation channels from the incident nuclei are almost the same for all projectiles at different energies, revealing that the modes of nuclear fragmentation are energy independent. The stripped processes with relativistic hydrogen and∕or helium fragments are the dominant in all projectiles. Helium fragments are the most frequent among the multiple charged fragments and the fractional yield of nuclear fragmentation channels without projectile fragments heavier than helium fragments is about $27\%$ of the total sample. The interactions in which the projectile nuclei break up into single charged particles only represent $\approx 14\%$ of the total sample and are mostly due to central collisions in which the majority of projectile nucleons have participated in the first stage of the collisions.

Figure 1

(a)–(d) The experimental (points with error bars) and calculated (curves) total charge distributions of nuclear fragments stripped in the interactions of $3.7A\mathrm{GeV}$ ${}^{24}\mathrm{Mg}$ projectile with: (a) $\mathrm{H}$, free and quasifree nucleon type $(n_{\mathrm{h}}=0,1)$, (b) $\mathrm{CNO}$ type $(2⩽n_{\mathrm{h}}⩽7)$, (c) $Em$ nuclei $(n_{\mathrm{h}}⩾0)$, and (d) $\mathrm{AgBr}$ type $(n_{\mathrm{h}}⩾8)$. The curves are the predictions of the extended Glauber model.

Figure 2

Charge distributions of nuclear projectile fragments emerged in ${}^{24}\mathrm{Mg}$ interactions with quasinucleon target $(n_{\mathrm{h}}=0,1)$ at $3.7A\mathrm{GeV}$. The curves are calculated by the bond percolation model with parameters $P=0.55$ and 0.60.

Figure 3

The multiplicity distributions of projectile fragments with charge $Z⩾2$ in interactions of $3.7A\mathrm{GeV}$ ${}^{24}\mathrm{Mg}$, $3.7A\mathrm{GeV}$ ${}^{28}\mathrm{Si}$ [26], and $14.6A\mathrm{GeV}$ ${}^{28}\mathrm{Si}$ [26] incident beams on the quasinucleon target. The curves are calculated according to the percolation model.

Figure 4

The relation between the average number of interacting projectile nucleons $⟨N_{\mathrm{int}}⟩$ and the number of heavily target fragments $n_{\mathrm{h}}$ in ${}^{24}\mathrm{Mg}$$Em$ interactions at $3.7A\mathrm{GeV}$.