Study of the light scalar a0 (980) through the decay D0 →a0 (980)-e+νe with a0 (980)- →ηπ

Using 7.93 fb-1 of e+e- collision data collected at a center-of-mass energy of 3.773 GeV with the BESIII detector, we present an analysis of the decay D0→ηπ-e+νe. The branching fraction of the decay D0→a0(980)-e+νe with a0(980)-→ηπ- is measured to be (0.86±0.17stat±0.05syst)×10-4. The decay dynamics of this process is studied with a single-pole parametrization of the hadronic form factor and the Flatté formula describing the a0(980) line shape in the differential decay rate. The product of the form factor f+a0(0) and the Cabibbo-Kobayashi-Maskawa matrix element |Vcd| is determined for the first time with the result f+a0(0)|Vcd|=0.126±0.013stat±0.003syst.