Absorption and Emission Spectra of an higher-dimensional Reissner-Nordström black hole

The absorption and emission problems of the brane-localized and bulk scalarsare examined when the spacetime is a (4+n)-dimensional Reissner-Nordströmblack hole. Making use of an appropriate analytic continuation, we computethe absorption and emission spectra in the full range of particle’s energy. Forthe case of the brane-localized scalar the presence of the nonzero inner horizonparameter r− generally enhances the absorptivity and suppresses the emissionrate compared to the case of the Schwarzschild phase. The low-energy absorp-tion cross section exactly equals to 4πr2+, two-dimensional horizon area. Theeffect of the extra dimensions generally suppresses the absorptivity and en-hances the emission rate, which results in the disappearance of the oscillatorypattern in the total absorption cross section when n is large. For the case ofthe bulk scalar the effect of r− on the spectra is similar to that in the case ofthe brane-localized scalar. The low-energy absorption cross section equals tothe area of the horizon hypersurface. In the presence of the extra dimensionsthe total absorption cross section tends to be inclined with a positive slope.It turns out that the ratio of the missing energy over the visible one decreaseswith increase of r−. ∗Email:[email protected]†Email:[email protected]