Measurement of Indirect C P-Violating Asymmetries in D[superscript 0] → K[superscript +] K[superscript −] and D[superscript 0] → π[superscript +] π[superscript −] Decays at CDF
T. Aaltonen, B. Álvarez González, S. Amerio, D. Amidei, A. Anastassov, A. Annovi, J. Antoš, G. Apollinari, J. A. Appel, T. Arisawa, A. Artikov, J Asaadi, W. Ashmanskas, B. Auerbach, Adam Aurisano, F. Azfar, W. Badgett, T. Bae, A. Barbaro‐Galtieri, V. E. Barnes · DSpace@MIT (Massachusetts Institute of Technology) · 2012
We report a measurement of the indirect CP-violating asymmetries (A[subscript Γ]) between effective lifetimes of anticharm and charm mesons reconstructed in D[superscript 0] → K[superscript +]K[superscript -] and D[superscript 0] → π[superscript +]π[superscript -] decays. We use the full data set of proton-antiproton collisions collected by the Collider Detector at Fermilab experiment and corresponding to 9.7 fb[superscript -1] of integrated luminosity. The strong-interaction decay D[superscript *+] → D[superscript 0]π[superscript +] is used to identify the meson at production as D[superscript 0] or [bar over D][superscript 0]. We statistically subtract D[superscript 0] and [bar over D][superscript 0] mesons originating from b-hadron decays and measure the yield asymmetry between anticharm and charm decays as a function of decay time. We measure A[subscript Γ](K[superscript +]K[superscript -]) = (-0.19 ± 0.15(stat) ± 0.04(syst))% and A[subscript Γ](π[superscript +]π[superscript -]) = (-0.01 ± 0.18(stat) ± 0.03(syst))%. The results are consistent with the hypothesis of CP symmetry and their combination yields A[subscript Γ] = (-0.12 ± 0.12)%.