Measurement of the time-integrated CP asymmetry in D 0 → KS 0 KS 0 decays

Abstract

Abstract: A measurement of the time-integrated CP asymmetry in D0 → K0 SK0 S decays is reported. The data correspond to an integrated luminosity of about 2 fb−1 collected in 2015-2016 by the LHCb collaboration in pp collisions at a centre-of-mass energy of 13 TeV. The D0 candidate is required to originate from a D∗+ → D0π + decay, allowing the determination of the flavour of the D0 meson using the pion charge. The D0 → K+K− decay, which has a well measured CP asymmetry, is used as a calibration channel. The CP asymmetry for D0 → K0 SK0 S is measured to be A CP (D0 → K0 SK0 S ) = (4.3 ± 3.4 ± 1.0)%, where the first uncertainty is statistical and the second is systematic. This result is combined with the previous LHCb measurement at lower centre-of-mass energies to obtain A CP (D0 → K0 SK0 S ) = (2.3 ± 2.8 ± 0.9)%. Keywords: Charm physics, CP violation, Flavor physics, Hadron-Hadron scattering (experiments)