Charge differences of 1/3 and 2/3 between D and U quarks
should be originated by the chirality differences with the vacuum.
The chiral U quark is assumed to have much more collisionary
interaction with the opposite chiral oscillating Higgs field and consequently a
2/3 charge.
https://www.flickr.com/photos/93308747@N05/collections/72157661751585432/
https://www.flickr.com/photos/93308747@N05/collections/72157661751585432/