Gravitational lensing in the weak field limit by a braneworld black hole
  Braneworld black holes existing today may be of primordial origin, or may even be produced in high energy particle collisions in the laboratory and in cosmic ray showers as well. These black holes obey a modified mass-radius relationship compared to standard Schwarzschild black holes. Using the variational principle we calculate the bending angle of a light ray near the horizon of a braneworld black hole in the weak field limit. We next derive the expressions of several lensing quantities like the Einstein radius and the magnification for a point light source. These expressions are modified compared to the lensing quantities for standard Schwarzschild black holes and contain the scale of the extra dimensions. 
A. S. Majumdar, Nupur Mukherjee