Nova Model of Inclusive Reactions

Abstract

A model for particle production is presented in which the features recently observed in inclusive distributions can be reproduced. The calculation emphasizes the role of resonance-like objects which are diffractively produced and decay mainly through cascade emission of pions. The cross section for producing these objects which we call novas is diffractive and does not depend on energy. As a function of nova mass it rises to a low mass maximum (below 2 GeV) and falls off in a way which is controlled by Regge behavior and duality. We then construct a zero-parameter model for the inclusive distributions which also gives many predictions about exclusive reactions. Among the many features which can be obtained in terms of this picture are: the rapid approach of scaling for secondaries with relatively large center-of-mass momentum; a slower approach for soft secondaries and the pseudoscaling observed at present machine energy in certain reactions; a simple connection between the transverse-momentum distribution, the longitudinal-momentum distribution, and the average multiplicity of secondaries; charge effects which should not vanish asymptotically; and a marked difference between meson and baryon distributions. The approach to scaling is connected to the rise of the diffractive cross section as inferred from the behavior of the $K^{+}p$ total cross section. One also obtains an understanding for the "quark frame" results and the center-of-mass isotropy of slow secondaries.