Multihadronic events atEc.m.=29 GeV and predictions of QCD models fromEc.m.=29 GeV toEc.m.=93 GeV

Multihadronic $e^{+}$ $e^{\mathrm{-}}$ annihilation events at a center-of-mass energy of 29 GeV have been studied with both the original (PEP 5) Mark II and the upgraded Mark II detectors. Detector-corrected distributions from global shape analyses such as aplanarity, $Q_2$-$Q_1$, sphericity, thrust, minor value, oblateness, and jet masses, and inclusive charged-particle distributions including x, rapidity, $p_{\perp }$, and particle flow are presented. These distributions are compared with predictions from various multihadron event models which use leading-logarithmic shower evolution or QCD matrix elements at the parton level and string or cluster fragmentation for hadronization. The new generation of parton-shower models gives, on the average, a better description of the data than the previous parton-shower models. The energy behavior of these models is compared to existing $e^{+}$ $e^{\mathrm{-}}$ data. The predictions of the models at a center-of-mass energy of 93 GeV, roughly the expected mass of the $Z^0$, are also presented.