Achard, P (reprint author), Univ Geneva, CH-1211 Geneva 4, Switzerland.
The reactions e(+)e(-) --> e(+)e(-)pi(0) X and e(+)e(-) --> e(+)e(-)K(S)(0) X are studied using data collected at LEP with the L3 detector at centre-of-mass energies between 189 and 202 GeV. Inclusive differential cross sections are measured as a function of the particle transverse momentum p(t) and the pseudo-rapidity. For p(t) less than or equal to 1.5 GeV, the pi(0) and K-S(0) differential cross sections are described by an exponential, typical of soft hadronic processes. For p(t) greater than or equal to 1.5 GeV, the cross sections show the presence of perturbative QCD processes, described by a power-law. The data are compared to Monte Carlo predictions and to NLO QCD calculations, (C) 2002 Elsevier Science B.V. All rights reserved.