Particle - anti-particle asymmetries in the production of baryons in 500-GeV/c pi- nucleon interactions

We present the Fermilab E791 measurement of baryon - antibaryon asymmetries in the production of Lambda^0, Cascade, Omega and Lambda_c in 500 GeV/c pi^- Nucleon interactions. Asymmetries have been measured as a function of x_F and p_T**2 over the range -0.12<x_F<0.12 and p_T**2<4$ (GeV/c)**2 for hyperons and -0.1<x_F<0.3 and p_T**2<8 (GeV/c)**2 for the Lambda_c baryons. We observe clear evidence of leading particle effects and a basic asymmetry even at x_F=0. These are the first high statistics measurements of the asymmetry in both the target and beam fragmentation regions in a fixed target experiment.