Study of the decay asymmetry parameter and CP violation parameter in the Λc+ → Λπ+ decay

Abstract Using data from the FOCUS (E831) experiment at Fermilab, we present a new measurement of the weak decay-asymmetry parameter α Λ c in Λ c + → Λ π + decay. Comparing particle with antiparticle decays, we obtain the first measurement of the CP violation parameter A ≡ α Λ c + α Λ ¯ c α Λ c − α Λ ¯ c . We obtain α Λ c = − 0.78 ± 0.16 ± 0.19 and A = − 0.07 ± 0.19 ± 0.24 where errors are statistical and systematic.