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Asymmetries in the Production of $Λ_c^+$ and $Λ_c^-$ Baryons in 500 GeV/c $π^-$ Nucleon Interactions

We present a measurement of asymmetries in the production of $Λ_c^+$ and $Λ_c^-$ baryons in 500 GeV/c $π^-$--nucleon interactions from the E791 experiment at Fermilab. The asymmetries were measured as functions of Feynman x ($x_F$) and transverse momentum squared ($p_T^2$) using a sample of $1819 \pm 62$ $Λ_c$'s observed in the decay channel $Λ_c \to pK^-π^+$. We observe more $Λ_c^+$ than $Λ_c^-$ baryons, with an asymmetry of $(12.7\pm3.4\pm1.3) %$ independent of $x_F$ and $p_T^2$ in our kinematical range $(-0.1 < x_F < 0.6$ and $0.0 < p_T^2 < 8.0 (GeV/c)^2$). This $Λ_c$ asymmetry measurement is the first with data in both the positive and negative $x_F$ regions.