Measurement of the charm mixing parameter $y_{CP}-y_{CP}^{K\pi }$ using two-body $D^0$ meson decays

Abstract

A measurement of the ratios of the effective decay widths of $D^0\to {\pi }^{-}{\pi }^{+}$ and $D^0\to K^{-}{K}^{+}$ decays over that of $D^0\to K^{-}{\pi }^{+}$ decays is performed with the LHCb experiment using proton-proton collisions at a centre-of-mass energy of $13\mathrm{TeV}$, corresponding to an integrated luminosity of $6\mathrm{f}{\mathrm{b}}^{-1}$. These observables give access to the charm mixing parameters $y_{CP}^{\pi \pi }-y_{CP}^{K\pi }$ and $y_{CP}^{KK}-y_{CP}^{K\pi }$, and are measured as $y_{CP}^{\pi \pi }-y_{CP}^{K\pi }=(6.57\pm 0.53\pm 0.16)\times 10^{-3}$, $y_{CP}^{KK}-y_{CP}^{K\pi }=(7.08\pm 0.30\pm 0.14)\times 10^{-3}$, where the first uncertainties are statistical and the second systematic. The combination of the two measurements is $y_{CP}-y_{CP}^{K\pi }=(6.96\pm 0.26\pm 0.13)\times 10^{-3}$, which is four times more precise than the previous world average.

All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2021-041.html (LHCb public pages)

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Cited by in corpus (4)

• 50 Years of Quantum Chromodynamics
• Heavy Flavour Physics and CP Violation at LHCb: a Ten-Year Review
• Measurement of $D^0-{\overline{D}}^0$ mixing and search for $CP$ violation with $D^0\to K^{+}{\pi }^{-}$ decays
• Model-independent measurement of $D^0$-$\overline{D}{}^0$ mixing parameters in $D^0\to K_S^0{\pi }^{+}{\pi }^{-}$ decays at Belle and Belle II