Test particle motion around a black hole in a braneworld

Analytical solutions of Maxwell equations in background spacetime of a black hole in a braneworld immersed in an external uniform magnetic field have been found. The influence of both magnetic and brane parameters on the effective potential of the radial motion of a charged test particle around a slowly rotating black hole in a braneworld immersed in a uniform magnetic field has been investigated by using the Hamilton-Jacobi method. An exact analytical solution for dependence of the radius of the innermost stable circular orbits (ISCO) ${r}_{\mathrm{ISCO}}$ from the brane parameter for the motion of a test particle around a nonrotating isolated black hole in a braneworld has been derived. It has been shown that the radius ${r}_{\mathrm{ISCO}}$ is monotonically growing with the increase of the module of the brane tidal charge. A comparison of the predictions on ${r}_{\mathrm{ISCO}}$ of the braneworld model and of the observational results of ISCO from relativistic accretion disks around black holes provided the upper limit for the brane tidal charge $\ensuremath{\lesssim}{10}^{9}\text{ }\text{ }{\mathrm{cm}}^{2}$.