Quark combinatorics and meson-production ratios in hadronic Z0 decays

A vast body of experimental data accumulated in the past few years ill hadronic Z(0) decays allows one to check quark-combinatories relations for a new type of processes - namely, quark jets in the decays Z(0) --> q (q) over bar --> hadrons. In this paper, we review quark - combinatorics rules for the yields of vector and pseudoscalar mesons, V/P, in the central and fragmentation regions of hadronic Z(0) decays. It is emphasized that, in the central region, a direct verification of quark-combinatorics rules is rather problematic because of a considerable background associated with the decay of highly excited resonances; however, such a verification is possible in the fragmentation region, at x(hadron) similar to 0.5-1, where the contribution of resonance decays is suppressed owing to a fast decrease of the spectra with increasing x(hadron). It is shown that, in the fragmentation region, experimental data on rho (0)/pi (0) and rho/pi (+) are in reasonable agreement with the predictions of quark combinatorics. The ratios of the heavy-meson yields, B*/B and D*/D, are also discussed: the data demonstrate good agreement with the quark combinatorial results. We analyze the structure of the suppression parameters for strange- and heavy-quark production in soft processes and estimate their orders of magnitude in multiperipheral processes; the ratio K (+/-)/pi (+/-) at x(hadron) similar to 0.5-0.8 and the production probabilities for c (c) over bar and b (b) over bar mesons are in good agreement with the estimates. (C) 2001 MAIK "Nauka/Interperiodica".