Can a photon move at another speed that's not the speed of light? I was reading an article about the new collider photon-photon, and the writer says "the scientists accelerate photons in a very high speed".
It's non sense to me, because as far I know a photon only moves on the speed of light. 
So my question is: Can a photon move at another speed that's not the speed of light?
EDIT:
This is the article about photon-photon collider:
http://www.theverge.com/2014/5/18/5724658/photon-collider-could-turn-light-into-matter
I found the snippet about accelerating photons at a very high speed in this Portuguese article:
http://meiobit.com/287429/colison-foton-foton-proposta-transformar-luz-em-materia/
 A: I think you are referring to a recent proposal to create matter with pure light (high energy photon-photon collisions):
http://www.nature.com/nphoton/journal/vaop/ncurrent/full/nphoton.2014.95.html
The article you were reading very likely misinterpreted something or confused "high energy" with "high speed".  Light (in a vacuum) only travels at the speed of light. 
A: Yes, normally $c$ is for speed of light in vacuum at which light travels at its maximum speed. However if I were to put, say, atmosphere or diamond in from of a light beam, the light would travel slower than $c$, therefore I conclude yes its possible to travel slower than the TRUE speed of light.
Next, to elaborate, in 1905, Einstein's miracle year, he proposed his mass-energy equivalence theory which is $E=mc^2$. This must mean, with some simple rearranging, we understand that mass can be converted in energy and vice-versa. That in mind, a photon is an packet of energy in basic definition. That in mind, we can convert the photons into mass using the formula rearranged: $m=E/c^2$ which means we can even make light travel even at 0 indirectly. 
