Amplitude analysis and branching-fraction measurement of \boldmath $D_{s}^{+} \to K^0_{S}\pi^{+}\pi^{0}$

TL;DR

This paper performs an amplitude analysis of the decay $D_{s}^{+} o K_{S}^{0} ho$, measuring the decay's branching fraction and intermediate processes using data from BESIII, advancing understanding of charm meson decays.

Contribution

The study provides the first detailed amplitude analysis and precise branching fraction measurement of $D_{s}^{+} o K_{S}^{0} ho ext{-like}$ decays, using BESIII data and a double-tag technique.

Findings

Measured branching fraction: (5.43 ± 0.30 ± 0.15) × 10^{-3}

Identified dominant intermediate processes such as $K_{S}^{0} ho(770)^{+}$

Provided phase differences and relative fractions of decay components.

Abstract

Utilizing a data set corresponding to an integrated luminosity of 6.32~$\rm fb^{-1}$, recorded by the BESIII detector at center-of-mass energies between 4.178 and 4.226~GeV, we perform an amplitude analysis of the decay $D_{s}^{+} \to K_{S}^{0}\pi^{+}\pi^{0}$ and determine the relative fractions and phase differences of different intermediate processes, which include $K_{S}^{0}\rho(770)^{+}$, $K_{S}^{0}\rho(1450)^{+}$, $K^{*}(892)^{0}\pi^{+}$, $K^{*}(892)^{+}\pi^{0}$, and $K^{*}(1410)^{0}\pi^{+}$. Using a double-tag technique, and making an efficiency correction that relies on our knowledge of the phase-space distribution of the decays coming from the amplitude analysis, the absolute branching fraction is measured to be $\mathcal{B}(D_{s}^{+} \to K_{S}^{0}\pi^{+}\pi^{0})=(5.43\pm0.30_{\text{stat}}\pm 0.15_{\text{syst}})\times 10^{-3}$.