Ratio of $\barΛ/Λ$ in Semi-inclusive Electroproduction

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

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