Model-independent measurement of charm mixing parameters in $\bar{B} \rightarrow D^0 ( \rightarrow K_S^0 \pi^+ \pi^-) \mu^- \bar{\nu}_\mu X$ decays

TL;DR

This paper reports a model-independent measurement of charm mixing and CP violation parameters using B meson decays collected by LHCb, providing results consistent with previous studies and combining with recent analyses for improved precision.

Contribution

It introduces a novel model-independent approach to measure charm mixing parameters in B decays, enhancing the understanding of charm CP violation.

Findings

Measured charm mixing parameters with statistical and systematic uncertainties.

Results are consistent with previous measurements and contribute to the global understanding.

Combined analysis with recent LHCb results improves the precision of charm mixing parameters.

Abstract

A measurement of charm mixing and $CP$-violating parameters is reported, using $\bar{B} \rightarrow D^0 ( \rightarrow K_S^0 \pi^+ \pi^-) \mu^- \bar{\nu}_\mu X$ decays reconstructed in proton-proton collisions collected by the LHCb experiment during the years 2016 to 2018, corresponding to an integrated luminosity of 5.4 fb$^{-1}$. The measured mixing and $CP$-violating parameters are $$x_{\rm CP} = [ \,\,\,\,\,4.29 \pm 1.48 \mbox{(stat)} \pm 0.26 \mbox{(syst)} ] \times 10^{-3}\,,$$ $$y_{\rm CP} = [ \,\,12.61 \pm 3.12 \mbox{(stat)} \pm 0.83 \mbox{(syst)} ] \times 10^{-3} \,,$$ $$\Delta x \,\,= [ -0.77 \pm 0.93 \mbox{(stat)} \pm 0.28 \mbox{(syst)} ] \times 10^{-3} \,,$$ $$\Delta y \, = [ \,\,\,\,\,3.01 \pm 1.92 \mbox{(stat)} \pm 0.26 \mbox{(syst)} ] \times 10^{-3} \,.$$ The results are complementary to and consistent with previous measurements. A combination with the recent LHCb analysis of $D^{*+} \rightarrow D^0 ( \rightarrow K_S^0 \pi^+ \pi^-) \pi^+ $ decays is reported.