Direct CP violation in Λb→n(Λ)π+π- decays via ρ-ω mixing

Abstract

We study direct CP violation in the bottom baryon decays Λb→fρ0(ω)→fπ+π- (f=n or Λ). It is found that in these decays via ρ-ω mixing the CP violation could be very large when the invariant mass of the π+π- pair is in the vicinity of the ω resonance. With a typical value Nc=2 in the factorization approach, the maximum CP-violating asymmetries are more than 50% and 68% for Λb→nπ+π- and Λb→Λπ+π-, respectively. With the aid of heavy quark symmetry and phenomenological models for the hadronic wave functions of Λb, Λ and the neutron, we estimate the branching ratios of Λb→n(Λ)ρ0.