Ratio of (Lambda)over-bar/Lambda in semi-inclusive electroproduction

It is shown that the Lambda/Lambda cross section ratio in semi-inclusive electroproduction of Lambda and Lambda hyperons in deep inelastic scattering of charged lepton on a nucleon target, can provide useful information on the quark to A fragmentation functions. This ratio is calculated explicitly in a quark-diquark model, a pQCD based analysis, and an SU(3) symmetry model, with three different options for the contribution from the unfavored fragmentation functions. The x-dependence of this ratio is sensitive to the ratio of unfavored fragmentation functions over favored fragmentation functions, D-u(Lambda) (z)/D-u(Lambda) (z), whereas the z-dependence is sensitive to the flavor structure of the fragmentation functions, i.e., the ratio D-u(Lambda) (z)/D-u(Lambda)(z). Future measurements by the HERMES Collaboration at DESY can discriminate between various cases. (C) 2003 Published by Elsevier B.V.Physics, MultidisciplinarySCI(E)2ARTICLE1-235-4057