Does Dirac equation for a generalized Coulomb-like potential in D+1   dimensional flat spacetime admit any solution for $D\geq 4$?
  The relativistic hydrogen atom in an Euclidean space-time of arbitrary number of space dimensions ($D$) plus one time dimension is revisited. In particular, numerical solutions of the radial Dirac equation for a generalized Coulombian potential proportional to $1/r^{(D-2)}$ are investigated. It is argued that one could not find any physical solution for $D\geq 4$. 
F. Caruso, J. Martins, L.D. Perlingeiro and V. Oguri
quant-ph