Impact Parameter Dependences of the Number of Interacting Nucleons and   Mean Multiplicities in High Energy Heavy Ion Interactions
  We consider the dependences of the average number of interacting nucleons in high energy heavy ion collisions on the impact parameter in two cases, when the colliding nuclei have equal atomic weights, and when one nucleus is significantly more heavy in comparison with the second one. We argue that in the case of trigger of some rare event (say, $J/\psi$, or $\Upsilon$ production) the multiplicity of the secondaries can change several times for minimum bias sample, but it should be stable in the case of central events. 
C.Pajares and Yu.M.Shabelski