2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/202688We show that both the multiplicity distribution and the ratio of factorial cumulants over factorial moments for 2-jet events in e+e- annihilation at the Z^0 peak can be well reproduced by the weighted superposition of two negative binomial distributions, associated to the contribution of $b\bar b$ and light flavoured events respectively. The negative binomial distribution is then suggested to describe the multiplicity distribution of 2-jet events with fixed flavour.LaTeX, 15 pages including 4 Postscript figures, uses epsfig.sty and rotating.styHigh Energy Physics - Phenomenologytext