Asymmetries in the production of Λc+ and Λc− 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 1 819±62 Λ c 's observed in the decay channel Λ c + → pK − π + . We observe more Λ c + than Λ c − baryons, with an asymmetry of (12.7±3.4±1.3)% 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.