Its part of iterative improvement. The resonance causes the beam to spread out, which both makes getting results harder and losing more particles in route. The resonance is caused by the magnets used being imperfect.

The point of the article is they have created a model that predicts these resonances accurately. This will be of limited benefit to them, though it will help clean up some data. The big advantage for future constructions is by knowing how the field becomes imperfect, measures can be taken to correct for it. This will make future particle accelerators better. The same problem will occur in larger fusion reactors. By studying this now, they can be improved before they are even built.

“In theory there is no difference between theory and practice. In practice there is a huge difference!”