Multiplicities associated with the production of pions, kaons or protons of high transverse momentum, at the ISR

In high-energy proton-proton collisions, the mean charged multiplicity M in the central region, associated with a high-PT hadron trigger at 90°, shows a linear dependence on both ln s and PT. M is measured to depend on the type (π±, K±, p or p) of the idenfied high-PT trigger particle.