PHENOMENOLOGY OF POWER CORRECTIONS IN FRAGMENTATION PROCESSES IN E(-)ANNIHILATION()E()

We analyse power corrections to longitudinal and transverse fragmentat ion processes in e(+)e(-) annihilation, based on the assumption of ult raviolet dominance of power corrections. Under this assumption, we det ermine the dependence of power corrections on the scaling variable x f rom the infrared renormalon asymptotics of leading power coefficient f unctions. Our results suggest that the longitudinal and transverse glu on fragmentation coefficient functions receive corrections of order 1/ (xQ)(2). The power expansion breaks down at x < Lambda/Q and has to be resummed. This resummation leads to 1/Q corrections to the longitudin al and transverse cross section, which cancel for the total cross sect ion. We provide a simple parametrization of the x dependence of 1/Q(2) corrections to fragmentation processes and investigate perturbative c orrections to the longitudinal cross section in higher orders, in view of a determination of the strong coupling. (C) 1997 Elsevier Science B.V.