A Proposed Test of Charge Symmetry in $\Sigma$ Decay
  The semi-leptonic decays of $\Sigma^\pm$ offer a vehicle for observing charge symmetry-breaking. The effect is expected to be about 6\%, enhanced due to the replacement of two u quarks by d quarks. We propose that present experimental data be improved to search for this effect. 
E.M. Henley and G.A. Miller