Analysis of the dynamics of the decay D+→KS0π0e+νe

The branching fraction of D⁺→K_S⁰π⁰e⁺ν_e is measured for the first time using 7.93 fb⁻¹ of e⁺e⁻ annihilation data collected at the center-of-mass energy s = 3.773 GeV with the BESIII detector operating at the BEPCII collider, and is determined to be BD⁺→K_S⁰π⁰e⁺ν_e=0.881±0.017_stat.±0.016_syst.%. Based on an analysis of the D⁺→K_S⁰π⁰e⁺ν_e decay dynamics, we observe the S-wave and P-wave components with fractions of f_S-wave = (6.13 ± 0.27_stat.± 0.30_syst.)% and f_K¯∗8920=93.88±0.27_stat.±0.29_syst.%, respectively. From these results, we obtain the branching fractions BD⁺→KS0π0_S−wavee⁺ν_e=5.41±0.35_stat.±0.37_syst.×10⁻⁴ and BD⁺→K¯^∗892⁰e⁺ν_e=4.97±0.11_stat.±0.12_syst.%. In addition, the hadronic form-factor ratios of D⁺→K¯^∗892⁰e⁺ν_e at q² = 0, assuming a single-pole dominance parameterization, are determined to be r_V=V0A₁0=1.43±0.07_stat.±0.03_syst. and r₂=A₂0A₁0=0.72±0.06_stat.±0.02_syst..