Measurement of the form factors in the decay ${\mathit{D}}^{+}$→K${\mathrm{¯}}^{\mathrm{*}0}$${\mathit{e}}^{+}$${\nu }_{\mathit{e}}$

We have measured the three form factors governing the decay ${\mathit{D}}^{+}$→K¯ ${}_{}{}^{\mathrm{*}0}{}_{}{}^{}$ ${\mathit{e}}^{+}$ ${\nu }_{\mathit{e}}$, observed in Fermilab photoproduction experiment E691, using the complete decay distribution of the data. The results are ${\mathit{A}}_1$(0)=0.46±0.05±0.05, ${\mathit{A}}_2$(0)=0.0±0.2±0.1, and V(0)=0.9±0.3±0.1 for the two axial-vector and the vector form factors, respectively. The K¯ ${}_{}{}^{\mathrm{*}0}{}_{}{}^{}$ mesons have a ratio of longitudinal to transverse polarization of 1.$8_{\mathrm{-}0.4}^{+0.6\mathrm{}}$±0.3. These results are significantly different from values predicted by a number of different models.