Feynman Diagram for Double Charm Baryon

[SnoliF]

This Feynman diagram accompanied the announcement on the public LHCb site. How would you describe the origins of the up and down quark anti-quark pairs that that contribute to the decay of the $\Xi_{cc}^{++}$?

 

[mfb]

Gluon-initiated. The gluons can come from anywhere, they are not drawn to keep the diagram simpler.

 

[SnoliF]

Thanks for the quick reply. After thinking about it for a few minutes, I figured it had to be gluons scattering from somewhere.