Hadron distributions in the reactions hadron + hadron → lepton pair + hadrons and two virtual photons → hadrons, and tests of the parton model

The parton model description of the hadron distribntioa can be characterized in terms of a fev fragmentation regions and plateaus. Re discuss suchdistributions in the reactions hadron + hadron -> lepton pair + hadrons and virtual photon + virtual photon -> hadrons, comparison of different distributions as tests of the parton model, and kinematical conditions for the validity of the asymptotic descriptions of the distributions and the tests. (Submitted to Phys. Rev.) * Work supported by the U. S. Atomic Energy Commission. The parton model description of the final state hadron distributions has been discussed for various processes, namely, the deep inelastic electro-production 173 , lepton + hadron -> lepton t hadrons, (1) 1-3 the high energy electron-positron annihilation , electron + positron -> hadrons,4 and the deep hadron-hadron scattering , (2) hadron + hadron -> large transverse momentum hadron + other hadrons (3) in certain kinematical regions. Such distributions always involve some fragmentation regions and plateaus with the heights of the plateaus, as vell as the shapes of the ' fragmentation regions, for different reactions related to one another. It is interesting to see if such descriptions also can be naturally extended to other reactions in terms of the existing fragmentation regions and plateaus. Furthermore, ve indeed need to study some other reactions in order to provide more tests of the parton model. Unless at extremely high energies, there is not enough phase space for the full structure of all these regions and therefore various regions may overlap. Thus it is difficult to use the full structure