Studies of the resonance structure in $D^0\to K^0_S K^{\pm}\pi^{\mp}$ decays

TL;DR

This paper analyzes the resonance structure in specific $D^0$ decay modes using LHCb data, determining amplitude parameters, measuring branching ratios, and searching for CP violation with no significant effects found.

Contribution

It introduces detailed amplitude models for $D^0$ decays, compares formulations for the $K ext{-}\pi$ S-wave, and provides precise measurements of branching ratios and CP symmetry tests.

Findings

Good description of data with two $K ext{-}\pi$ S-wave models

Measured ratio of branching fractions with high precision

No significant CP violation observed in the decay modes

Abstract

Amplitude models are applied to studies of resonance structure in $D^0\to K^0_S K^- \pi^+$ and $D^0\to K^0_S K^+ \pi^-$ decays using $pp$ collision data corresponding to an integrated luminosity of $3.0\,\mathrm{fb}^{-1}$ collected by the LHCb experiment. Relative magnitude and phase information is determined, and coherence factors and related observables are computed for both the whole phase space and a restricted region of $100\,\mathrm{MeV/}c^2$ around the $K^{*}(892)^{\pm}$ resonance. Two formulations for the $K\pi$ $S$-wave are used, both of which give a good description of the data. The ratio of branching fractions $\mathcal{B}(D^0\to K^0_S K^+ \pi^-)/\mathcal{B}(D^0\to K^0_S K^- \pi^+)$ is measured to be $0.655\pm0.004\,(\textrm{stat})\pm0.006\,(\textrm{syst})$ over the full phase space and $0.370\pm0.003\, (\textrm{stat})\pm0.012\,(\textrm{syst})$ in the restricted region. A search for $CP$ violation is performed using the amplitude models and no significant effect is found. Predictions from $SU(3)$ flavor symmetry for $K^{*}(892)K$ amplitudes of different charges are compared with the amplitude model results.