Fragmentation functions using e+e- data from PETRA and LEP
  We investigate fragmentation of charged particles in e+e- annihilation at 22, 35 and 44 GeV in terms of their polar angle and momentum distributions. From the angular distribution the ratio of longitudinal to total hadronic cross-section was determined at an average energy scale of 36.6 GeV to be $\sigma_L / \sigma_{tot} = 0.076 \pm 0.013$. At next-to-leading order this yields $ \alpha_S (36.6 GeV) = 0.150 \pm 0.025 $. The $\xi = \ln (1/x)$ distributions were used in conjunction with OPAL data from 91-208 GeV to study the scale dependence of the maximum position, $\xi_0$. We studied flavour dependence of $\xi_0$ as a possible explanation of this problem, using direct flavour dependent measurements of $\xi_0$ at 91 GeV by OPAL. 
Mona Blumenstengel (MPI, Munich), Stefan Kluth (MPI, Munich)