Inclusive π±, K± and(p,bar p) differential cross-sections in hadronic decays of the Z have been measured as a function of z= P hadron/ P beam, the scaled momentum. The results are based on approximately 520 000 events measured by the ALEPH detector at LEP during 1992. Charged particles are identified by their rate of ionization energy loss in the ALEPH Time Projection Chamber. The position, ξ*, of the peak in the ln(1/ z) distribution is determined, and the evolution of the peak position with centre-of-mass energy is compared with the prediction of QCD.
