Measurement of the charm-mixing parameter $y_{CP}$

TL;DR

This paper reports a precise measurement of the charm-mixing parameter y_{CP} using specific D^0 decay modes from B meson decays in proton-proton collisions, confirming previous results with improved accuracy.

Contribution

First measurement of y_{CP} using semimuonic B decays at LHCb, providing a more precise value consistent with the world average.

Findings

Measured y_{CP} as (0.57 ± 0.13(stat.) ± 0.09(syst.))%

Results agree with previous measurements and improve precision

Utilized data from proton-proton collisions at 7 and 8 TeV with 3 fb^{-1} luminosity

Abstract

A measurement of the charm-mixing parameter $y_{CP}$ using $D^0 \to K^+ K^-$, $D^0 \to \pi^+ \pi^-$, and $D^0 \to K^- \pi^+$ decays is reported. The $D^0$ mesons are required to originate from semimuonic decays of $B^-$ and $\overline{B}^0$ mesons. These decays are partially reconstructed in a data set of proton-proton collisions at center-of-mass energies of 7 and 8 TeV collected with the LHCb experiment and corresponding to an integrated luminosity of 3 fb$^{-1}$. The $y_{CP}$ parameter is measured to be $(0.57 \pm 0.13(\rm{stat.}) \pm 0.09(\rm{syst.}))\%$, in agreement with, and as precise as, the current world-average value.