As far as I know, according to quantum field theory, there are some photons that go faster than c, which is the speed of light in vacuum.
However, there seems to be a paper and a corresponding experiment that show every photon obeys the speed limit of $c$. (http://physics.aps.org/synopsis-for/10.1103/PhysRevLett.106.243602)
So, my question is:
Is this experiment accepted universally?
Regardless of the acceptance of the experiment, if every single photon is shown to obey the speed limit of $c$, what does this mean for quantum field theory?