Black hole collision with a scalar particle in four-, five-, and seven-dimensional anti-de Sitter spacetimes: Ringing and radiation

In this work we compute the spectra, waveforms, and total scalar energy radiated during the radial infall of a small test particle coupled to a scalar field into a d-dimensional Schwarzschild-anti-de Sitter black hole. We focus on d=4, 5, and 7, extending the analysis we have done for d=3. For small black holes, the spectra peaks strongly at a frequency omegasimilar tod-1, which is the lowest pure anti-de Sitter (AdS) mode. The waveform vanishes exponentially as t-->infinity, and this exponential decay is governed entirely by the lowest quasinormal frequency. This collision process is interesting from the point of view of the dynamics itself in relation to the possibility of manufacturing black holes at CERN LHC within the brane world scenario, and from the point of view of the AdS/CFT conjecture, since the scalar field can represent the string theory dilaton, and 4, 5, and 7 are dimensions of interest for the AdS/CFT correspondence.