SIMPLE UNDERSTANDING OF THE ENERGY DEPENDENCE OF THE B/M RATIO AND HADRON MULTIPLICITIES IN e+e− ANNIHILATION

Abstract

With the help of the color dipole model (CDM) in describing the parton shower process in the perturbative phase in e+e− annihilation, we extend the quark combination model (QCM) of the original form to a more general one in a multiparton system. Then we derive baryon and meson multiplicity formulas for the multiparton system. The new multiplicity formulas are expressed in terms of CDM quantities [Formula: see text] and [Formula: see text]. From these formulas, we can readily understand that the energy behavior of the B/M ratio implied by the multiplicity data in e+e− annihilation is the consequence of two competitive processes: one is the dipole splitting which makes B/M decrease and the other is the increase in combination chain length which makes it higher. To check these basic formulas further, we give multiplicities of most ground hadrons at three energies, 10, 30, 90 GeV, by using five main energy-independent parameters, 75% of which agree with data within 1.5 standard error.