Neutrinos with velocities greater than c ?
  A possible explanation of the results of the OPERA experiment is presented. Assuming that the usual value of c should be interpreted as the velocity of light in dark matter, we call the "true" velocity of light in vacuum, $c_t$. Then the OPERA neutrinos can be faster than c but slower than $c_t$. We also discuss the relationship between $c_t$ and neutrino masses. 
Joseph Schechter and M. Naeem Shahid
hep-ph