New results on CP violation in the charm sector

<!--HTML-->The difference in CP violation between the D0→K+K– and D0→π+π– decays (ΔACP) has emerged as an interesting observable to search for matter-antimatter asymmetries in the charm sector. By taking the difference between the two modes, most of the asymmetries induced by the detector or coming from the production mechanism cancel. A previous LHCb measurement, using 0.6 fb–1 of data, gave 3.5σ evidence for CP violation in the charm sector, which was further strengthened by results from the CDF and Belle collaborations. We present an update of the ΔACP measurement, consisting of two independent analyses, both using the full 2011 data set of 1.0 fb–1. In the first, the initial flavour of the D meson (D0 or D0-bar) is inferred from the charge of the slow pion in the decay D*+→D0π+, as in the previous publication. The second uses D mesons produced in semileptonic B decays, where the charge of the associated muon provides the tag.