MULTIPLICITY, ASYMMETRY, AND INELASTICITY IN ULTRAHIGH-ENERGY N--N INTERACTIONS.

It has been shown (1) that most of the features of ultrahigh-energy interactions can be explained on the basis of the fireball model (2). However, there remain some interactions which exhibit an anomalous behavior that cannot be reconciled with the fireball model or the Fermi (a) model. The parameters which reflect sensitively the different behavior are multiplicity, asymmetry and inelasticity in an interaction. The very low multiplicity and the wide distribution in asymmetry and inelasticity are some of the observed features which need to be explained. The variation is too large to be explained by statistical fluctuations. Such a behavior many have deeper significance and could be possibly related to the internal structure of a nucleon. Recently, F~.VN~AN (4) has proposed that nucleons can be assumed to consist of free, structureless constituents called partons. For such a description an infinite-momentum frame of reference is assumed. The center-of-mass system for proton-proton interactions at ultrahigh energies is a good approximation to such a frame. The parton model (~) is used here to account for features of ultrahigh-energy interactions (--~ 10 x~ eV) that are in disagreement with both the fireball and the Fermi models. The dominant contribution of fireballs to particle production was shown analytically (x) for events whose primary energies ranged from 0.4 to 100 TeV. The bimodal angular distribution can be explained only on the basis of production of forward and backward fireballs in the center-of-mass system. However, it was found that for some events like 2+ 12p (5), 0+ 7p (6) and 4+ 19p (~), by following the procedure mentioned in