Angular profile of Particle Emission from a Higher-dimensional Black
  Hole: Analytic Results
  During the spin-down phase of the life of a higher-dimensional black hole,
the emission of particles on the brane exhibits a strong angular variation with
respect to the rotation axis of the black hole. It has been suggested that this
angular variation is the observable that could disentangle the dependence of
the radiation spectra on the number of extra dimensions and angular momentum of
the black hole. Working in the low-energy regime, we have employed analytical
formulae for the greybody factors, angular eigenvalues and eigenfunctions of
fermions and gauge bosons, and studied the characteristics of the corresponding
angular profiles of emission spectra in terms of only a few dominant partial
modes. We have confirmed that, in the low-energy channel, the emitted gauge
bosons become aligned to the rotation axis of the produced black hole while
fermions form an angle with the rotation axis whose exact value depends on the
angular-momentum of the black hole. In the case of scalar fields, we
demonstrated the existence of a "spherically-symmetric zone" that is followed
by the concentration of the emission on the equatorial plane, again in total
agreement with the exact numerical results.
