Study of weak radiative decays of D0→Vγ

The weak radiative decay of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:msup><a:mi>D</a:mi><a:mn>0</a:mn></a:msup><a:mo stretchy="false">→</a:mo><a:mi>V</a:mi><a:mi>γ</a:mi></a:math> with <d:math xmlns:d="http://www.w3.org/1998/Math/MathML" display="inline"><d:mi>V</d:mi><d:mo>=</d:mo><d:msup><d:mover accent="true"><d:mi>K</d:mi><d:mo stretchy="false">¯</d:mo></d:mover><d:mn>0</d:mn></d:msup></d:math>, and <h:math xmlns:h="http://www.w3.org/1998/Math/MathML" display="inline"><h:mi>ϕ</h:mi></h:math>, <j:math xmlns:j="http://www.w3.org/1998/Math/MathML" display="inline"><j:msup><j:mi>ρ</j:mi><j:mn>0</j:mn></j:msup></j:math>, and <l:math xmlns:l="http://www.w3.org/1998/Math/MathML" display="inline"><l:mi>ω</l:mi></l:math>, is systematically studied in the vector meson dominance model. It allows us to distinguish the short-distance mechanisms which can be described by the tree-level transitions in the nonrelativistic constituent quark model, and the long-distance mechanisms which are related to the final-state interactions (FSIs). We find that the FSI effects play a crucial role in <n:math xmlns:n="http://www.w3.org/1998/Math/MathML" display="inline"><n:msup><n:mi>D</n:mi><n:mn>0</n:mn></n:msup><n:mo stretchy="false">→</n:mo><n:mi>V</n:mi><n:mi>γ</n:mi></n:math> and the SU(3) flavor symmetry can provide a natural constraint on the relative phase between the short and long-distance transition amplitudes. Our analysis suggests that the <q:math xmlns:q="http://www.w3.org/1998/Math/MathML" display="inline"><q:mi>D</q:mi></q:math>-meson weak radiative decays can serve as a good case for investigating the nonperturbative QCD mechanisms at the charm quark mass region.