They have been doing this for years, and have accumulated a substantial data set. Could they just be lying? Maybe.
Things with mass cannot reach the speed of light because thats the limit on how fast things can go. When you near light speed, your mass increases exponentially, so that if you were trying to actually go the speed of light with something as massive as say, a sheet of paper, it would take more energy then there is in the universe to do it. Right?
Well maybe neutrinos are the particles that are actually without mass. Light may have like .00001% the mass of any other particle, yet still have mass, and therefore subject to the exponential increase in the energy it takes to propel the particle. Accounting for the "slowness" of light when compared to neutrinos.
Probably not, but if so, I called it.