multiplicity distributions in $p\bar{p}$ collisions at the CERN and Fermilab colliders. In those distribution, one sees a shoulder developing at high multiplicity at an energy of 540 GeV, which turns into a noticeable bump at higher energies. The real cause of this structure is not known, but may be due to minijet production. If plasma is nucleated in some fraction of central nucleus–nucleus collisions at the AGS, a similar structure may develop.

Kinetic Model of Hard Nucleon-Nucleon Collisions
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In this section we develop a simple kinetic model which allows us to estimate the number of high energy nucleon-nucleon scatterings occurring in the high density medium formed during a collision between heavy nuclei. These scatterings occur when a projectile nucleon penetrates the hot and dense matter to collide with a target nucleon which has also penetrated the hot and dense matter. The energy loss of the colliding nucleons must be taken into account to obtain a reasonable estimate of the energy available for meson production in the nucleon-nucleon collision.

To first approximation we can visualize the initial stage of a heavy ion collision at the AGS in the nucleus-nucleus center-of- momentum frame as two colliding Lorentz contracted disks. See Figure 