Measurement of mixing and CP violation parameters in two-body charm decays

TL;DR

This paper reports measurements of mixing and CP violation parameters in D0 mesons using LHCb data, providing insights into charm quark behavior and CP symmetry breaking.

Contribution

It presents the first measurement of y_CP and A_Γ parameters in D0 decays using a data-driven correction method for lifetime biases.

Findings

y_CP = (5.5 ± 6.3_{stat} ± 4.1_{syst}) × 10^{-3}

A_Γ = (-5.9 ± 5.9_{stat} ± 2.1_{syst}) × 10^{-3}

Results are consistent with no CP violation within uncertainties.

Abstract

A study of mixing and indirect CP violation in D0 mesons through the determination of the parameters y_CP and A_\Gamma\ is presented. The parameter y_CP is the deviation from unity of the ratio of effective lifetimes measured in D0 decays to the CP eigenstate K+K- with respect to decays to the Cabibbo favoured mode K-\pi+. The result measured using data collected by LHCb in 2010, corresponding to an integrated luminosity of 29 pb^-1, is y_CP = (5.5+/-6.3_{stat}+/-4.1_{syst}) x 10^-3. The parameter A_\Gamma\ is the asymmetry of effective lifetimes measured in decays of D0 and anti-D0 mesons to K+K-. The result is A_\Gamma\ = (-5.9+/-5.9_{stat}+/-2.1_{syst}) x 10^-3. A data-driven technique is used to correct for lifetime-biasing effects.