Measurements of charm mixing and CP violation using D[superscript 0] → K [supercript ±]π [superscript ∓] decays

Abstract

Measurements of charm mixing and CP violation parameters from the decay-time-dependent ratio of D[superscript 0]→K[superscript +]π[superscript -] to D[superscript 0]→K[superscript -]π[superscript +] decay rates and the charge-conjugate ratio are reported. The analysis uses [bar over B]→D[superscript *+]μ[superscript -]X, and charge-conjugate decays, where D[superscript *+]→D[superscript 0]π[superscript +], and D[superscript 0]→K[superscript ∓]π[superscript ±]. The pp collision data are recorded by the LHCb experiment at center-of-mass energies √s =7 and 8 TeV, corresponding to an integrated luminosity of 3 fb[superscript -1]. The data are analyzed under three hypotheses: (i) mixing assuming CP symmetry, (ii) mixing assuming no direct CP violation in the Cabibbo-favored or doubly Cabibbo-suppressed decay amplitudes, and (iii) mixing allowing either direct CP violation and/or CP violation in the superpositions of flavor eigenstates defining the mass eigenstates. The data are also combined with those from a previous LHCb study of D[superscript 0]→Kπ decays from a disjoint set of D[superscript *+] candidates produced directly in pp collisions. In all cases, the data are consistent with the hypothesis of CP symmetry.