Peripheral fragmentation of relativistic $^{11}$B nuclei in photoemulsion

Experimental results on peripheral fragmentation of relativistic $^{11}$B nuclei are presented. In the experiment the emulsions exposured to $^{11}$B beam with momentum 2.75 A GeV/c at the JINR Nuclotron are used. The relative probability of various fragmentation channels for nucleus breakups (class A) and more violent peripheral interactions (class B) have been determined. For classes under investigations the sum of the fragment charges in narrow forward cone is equal to the projectile charge, but in the events of class A there are no secondary particles and in the events of class B there are. In both classes the main channels is $^{11}$B$\to$2He+X: 62% and 50%, corresponding. The main channel $^{11}$B$\to$2(Z$_{fr}$=2)+(Z$_{fr}$=1) was investigated in details. Momentum measurements of single-charged fragments have been done to determine number of p, d and t in the channel. This way it was found that the ratio N$_{p}$ : N$_{d}$ : N$_{t}$ is about 1:1:1 for $^{11}$B nuclei dissociation and about 15:5:1 for peripheral interactions of $^{11}$B nuclei.