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

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 $mathcal{B}(D_{s}^{+} to K_{S}^{0}pi^{+}pi^{0})=(5.43pm0.30_{text{stat}}pm 0.15_{text{syst}})times 10^{-3}$.