Maximal Acceleration Corrections to the Lamb Shift of Muonic Hydrogen
  The maximal acceleration corrections to the Lamb shift of muonic hydrogen are calculated by using the relativistic Dirac wave functions. The correction for the $2S-2P$ transition is $\sim 0.38$ meV and is higher than the accuracy of present QED calculations and of the expected accuracy of experiments in preparation. 
C.X. Chen, G. Papini, N. Mobed and G. Lambiase, G. Scarpetta