Amplitude analysis and branching fraction measurement of the decay $ {D}^0\to {K}_S^0{\pi}^0{\pi}^0 $

An amplitude analysis of the decay ${D}^0\to {K}_S^0{\pi}^0{\pi}^0$ is performed to determine the relative magnitudes and phases of different intermediate processes. The analysis uses e + e − collision data collected at the center-of-mass energy of 3.773 GeV by the BESIII detector corresponding to an integrated luminosity of 20.3 fb − 1 . The absolute branching fraction of ${D}^0\to {K}_S^0{\pi}^0{\pi}^0$ is measured to be (1.026 ± 0.008 stat . ± 0.009 syst . )%. The dominant intermediate process is ${D}^0\to {\overline{K}}^{\ast }{(892)}^0\left(\to {K}_S^0{\pi}^0\right){\pi}^0$ , with a branching fraction of (4.10 ± 0.10 stat . ± 0.07 syst . ) × 10 − 3 .