Re: Swarm or supercedure?
That would be my guess since the queen cells are capped and the old queen is still there. How many queen cells were there? The times I've seen a supersedure take place there weren't more than three or four capped cells, sometimes only one or two.
You could move the older queen into a nuc if you have the resources from that hive or treat it as if you're introducing a queen, using a queen cage, to unrelated bees in a nuc. If the supersedure queen (new queen) doesn't return from her mating flight, you have the mother queen to put back in the original hive.
Keep us informed.
"Sometimes the best action, with bees, is no action at all."