Model-independent measurement of mixing parameters in $D^0 \to K_S \pi^+ \pi^-$ decays

TL;DR

This paper reports the first model-independent measurement of charm mixing parameters in the decay $D^0 o K_S \pi^+\pi^-$ using LHCb data, providing precise values for mixing parameters with statistical and systematic uncertainties.

Contribution

It introduces a novel model-independent approach to measure charm mixing parameters in $D^0$ decays, utilizing LHCb collision data for the first time.

Findings

Measured mixing parameters: x = (-0.86 ± 0.53 ± 0.17) × 10^{-2}

Measured mixing parameters: y = (+0.03 ± 0.46 ± 0.13) × 10^{-2}

Results are consistent with previous measurements and improve model independence.

Abstract

The first model-independent measurement of the charm mixing parameters in the decay $D^0 \to K_S \pi^+ \pi^-$ is reported, using a sample of $pp$ collision data recorded by the LHCb experiment, corresponding to an integrated luminosity of 1.0 fb$^{-1}$ at a centre-of-mass energy of 7 TeV. The measured values are \begin{eqnarray*} x &=& (-0.86 \pm 0.53 \pm 0.17) \times 10^{-2}, \\ y &=& (+0.03 \pm 0.46 \pm 0.13) \times 10^{-2}, \end{eqnarray*} where the first uncertainties are statistical and include small contributions due to the external input for the strong phase measured by the CLEO collaboration, and the second uncertainties are systematic.