Next-to-leading order fragmentation functions for pions and kaons

33 pp. (1995).
We present new sets of fragmentation functions for charged pions and kaons, both at leading and next-to-leading order. They are fitted to TPC data taken at energy $\sqrt s=3D29$GeV and describe excellently a wealth of other $e~+e~-$ data on charged-hadron production, ranging from $\sqrt s=3D5.2$GeV way up to LEP1 energy. They also agree with data on the production of neutral pions and kaons, if one makes the natural assumption that the respective fragmentation funct= ions are related to the charged counterparts by SU(2) symmetry. We also list simple parameterizations of the $x$ and $Q~2$ dependence of our results, which may be implemented conveniently in applications.