Superluminal Neutrinos in a Pseudoscalar Potential
  The superluminal propagation of neutrinos observed by OPERA collaboration can be interpreted as neutrinos traveling in a pseudoscalar potential which may be generated by a medium. The OPERA differential arrival time data set a constraint on the form of the pseudoscalar potential. 
Sarira Sahu, Bing Zhang
hep-ph astro-ph.HE