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Observation of the electromagnetic Dalitz decay <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mi>D</mml:mi><mml:mrow><mml:mo>*</mml:mo><mml:mn>0</mml:mn></mml:mrow></mml:msup><mml:mo stretchy="false">→</mml:mo><mml:msup><mml:mi>D</mml:mi><mml:mn>0</mml:mn></mml:msup><mml:msup><mml:mi>e</mml:mi><mml:mo>+</mml:mo></mml:msup><mml:msup><mml:mi>e</mml:mi><mml:mo>−</mml:mo></mml:msup></mml:math>
Based on $3.19\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of ${e}^{+}{e}^{\ensuremath{-}}$ collision data accumulated at the center-of-mass energy 4.178 GeV with the BESIII detector operating at the BEPCII collider, the electromagnetic Dalitz decay ${D}^{*0}\ensuremath{\rightarrow}{D}^{0}{e}^{+}{e}^{\ensuremath{-}}$ is observed for the first time with a statistical significance of $13.2\ensuremath{\sigma}$. The ratio of the branching fraction of ${D}^{*0}\ensuremath{\rightarrow}{D}^{0}{e}^{+}{e}^{\ensuremath{-}}$ …