Evidence for CP Violation in Time-Integrated D0→h−h+ Decay Rates

Abstract

A search for time-integrated C P violation in D 0 → h − h + ( h = K , π ) decays is presented using 0.62 fb − 1 of data collected by LHCb in 2011. The flavor of the charm meson is determined by the charge of the slow pion in the D * + → D 0 π + and D * − → ¯¯¯ D 0 π − decay chains. The difference in C P asymmetry between D 0 → K − K + and D 0 → π − π + , Δ A C P ≡ A C P ( K − K + ) − A C P ( π − π + ) , is measured to be [ − 0.82 ± 0.21 ( stat ) ± 0.11 ( syst ) ] % . This differs from the hypothesis of C P conservation by 3.5 standard deviations.