Measurement of the hadronic form factor in D0→K-e+νe decays

The shape of the hadronic form factor f+(q2) in the decay D0→K-e+νe has been measured in a model independent analysis and compared with theoretical calculations. We use 75  fb-1 of data recorded by the BABAR detector at the PEP-II electron-positron collider. The corresponding decay branching fraction, relative to the decay D0→K-π+, has also been measured to be RD=B(D0→K-e+νe(γ))/B(D0→K-π+(γ))=0.927±0.007±0.012. From these results, and using the present world average value for B(D0→K-π+), the normalization of the form factor at q2=0 is determined to be f+(0)=0.727±0.007±0.005±0.007 where the uncertainties are statistical, systematic, and from external inputs, respectively.