Measurements of direct CP violating asymmetries in charmless decays of strange bottom mesons and bottom baryons

Abstract

We report measurements of direct CP—violating asymmetries in charmless decays of neutral bottom hadrons to pairs of charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using a data sample corresponding to 1 fb−1 of integrated luminosity, we obtain the first measurements of direct CP violation in bottom strange mesons, ACP(B0s→K−π+)=+0.39±0.15(stat)±0.08(syst), and bottom baryons, ACP(Λ0b→pπ−)=+0.03±0.17(stat)±0.05(syst) and ACP(Λ0b→pK−)=+0.37±0.17(stat)±0.03(syst). In addition, we measure CP violation in B0→K+π− decays with 3.5σ significance, ACP(B0→K+π−)=−0.086±0.023(stat)±0.009(syst), in agreement with the current world average. Measurements of branching fractions of B0s→K+K− and B0→π+π− decays are also updated.