A parametrization of the properties of quark jets

A model is analyzed that provides a parametrization of the properties of the jet of mesons generated by a fast outgoing quark. It is assumed that the meson that contains the original quark leaves momentum and flavor to a remaining jet in which the particles are distributed (except for scaling of the energy and possible changes of flavor) like those of the original jet. One function, the probability f(η) that the remaining jet has a fraction η of the momentum of the original jet, is chosen (as a parabola) so the final distribution of charged hadrons agrees with data from lepton experiments. All the properties of quark jets are determined from f(η) and three parameters; the degree that SU(3) is broken in the formation of new quark-antiquark pairs (s[bar]s is taken as half as likely as uu[bar]), the spin nature of the primary mesons (assumed to be vector and pseudoscalar with equal probability), and the mean transverse momentum given to these primary mesons. Monte Carlo methods are used to generate typical jets. Analytic approximations are also given. Many features of quark jets are examined. The distribution of momentum of various hadrons D_q^h(z), the properties of the hadrons of largest momentum in the jet, correlations, rapidity-gap distribution of charge and of transverse momentum are some of the subjects discussed. The appearance of the jets to an instrument sensitive only to particles above some minimum momentum is also described. Although the model is probably not a true description of the physical mechanism responsible for quark jets, many predictions of the model seem quite reasonable, possibly much like real quark jets (except that the possibility of the emission of baryons is disregarded). The purpose of this work is to provide a model useful in the design of experiments in which quark jets may be observed, and further to provide a standard to facilitate the comparison of lepton-generated jets with the high-p⊥ jets found in hadron collisions