The contribution of ${\Sigma }^{\ast }\to \Lambda \pi$ to measured $\Lambda$ polarization

Abstract

Calculations of the polarization of $\Lambda$ and $\bar{\Lambda }$ particles after fragmentation of a polarized quark produced in processes like $Z$-decay and deep inelastic polarized lepton scattering must include $\Lambda$ and $\bar{\Lambda }$ produced as decay products of ${\Sigma }^0$ and ${\Sigma }^{\ast }$ as well as those produced directly. These decay contributions are significant and not feasibly included in theoretical calculations based on QCD without additional input from other experimental data. Furthermore these contributions depend on the spin structure of the ${\Sigma }^0$ or ${\Sigma }^{\ast }$ and are not directly related to the structure function of the $\Lambda$

6 pages, 1 figure