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

By using 6.32 fb −1 of data collected with 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 π +, K *(892)+ π 0, and K *(1410)0 π +. With the detection efficiency based on the amplitude analysis results, the absolute branching fraction is measured to be $ℬ\left({D}_{s}^{+}\to {K}_{S}^{0}{\pi }^{+}\pi 0\right)=\left(5.43±{0.30}_{\text{stat}}±{0.15}_{\text{syst}}\right)×{10}^{-3}$ .