The experiment was NOT done in a vacuum. From the end of the article:
“To reach Gran Sasso, the neutrinos pushed out from a special installation at CERN - also home to the Large Hadron Collider probing the origins of the universe - have to pass through water, air and rock.”
So, what’s the big deal? Am I missing something?
A vacuum has nothing to do with it. They are talking about neutrinos going faster than C, the theoretical speed of light. Not faster than some photons that were racing alongside.