Ratio of $\bar{\hat{I}}›/\hat{I}›$ in Semi-inclusive Electroproduction

Abstract

It is shown that the $\bar{\hat{I}}›/\hat{I}›$ cross section ratio in semi-inclusive electroproduction of $\hat{I}›$ and $\bar{\hat{I}}›$ hyperons in deep inelastic scattering of charged lepton on a nucleon target, can provide useful information on the quark to $\hat{I}›$ 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, $D_{\bar{u}}^{\hat{I}}›(z)/D_u^{\hat{I}}›(z)$, whereas the $z$-dependence is sensitive to the flavor structure of the fragmentation functions, i.e., the ratio $D_u^{\hat{I}}›(z)/D_s^{\hat{I}}›(z)$. Future measurements by the HERMES Collaboration at DESY can discriminate between various cases.

11 latex files, 6 figures