ETD

• AGamma
• CP violation
• heavy flavour physics
• quark charm
• trigger

Time-dependent CP asymmetries in the decay rates of the D0 and D0bar mesons into the CP-symmetric, singly Cabibbo-suppressed final states K+K− and π+π− are measured in pp collisions collected by the LHCb experiment in 2015 and in 2016 at the centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 1.7 fb−1. The strong-interaction decay D∗+ → D0π+ is used to infer the flavour of the D0 meson at production. The asymmetry between the effective decay widths of the D0 and D0bar decays, sensitive to indirect CP violation, is measured:
AΓ(D0 → K+K−) = (−60.9 ± 3.8 ± 0.6) · 10−4, AΓ(D0 → π+π−) = (−62.5 ± 6.7 ± 0.5) · 10−4,
where the first uncertainty is statistical, the second one systematic and the central values are blinded pending the receipt of the approval of the analysis procedure by the LHCb collaboration. The obtained statistical precision is comparable to the previous, world-leading measurement of AΓ by the LHCb collaboration, whereas the systematic uncertainty is reduced by about a factor of 2.