A search for time-integrated CP violation in D0 → h−h+ decays

Abstract

The preliminary results of a search for time-integrated CP violation in D0 → h−h+ (h = K, π) decays performed with 0.6 fb− of data collected by LHCb in 2011 are presented. The flavour of the charm meson is determined by the charge of the slow pion in the D*+ → D0π+ and D*− → D¯ 0 π− ${ar D^0}{pi ^ - }$ decay chains. The difference in CP asymmetry between D0 → K−K+ and D0 → π−π+, ΔACP ≡ ACP(K−K+) − ACP(π−π+), is measured to be ΔACP = |−0.82 ± 0.21(stat.) ± 0.11(syst.)|%. This differs from the hypothesis of CP conservation by 3.5σ.