Daisuke Ida

We study the boundary value problem for stationary rotating black hole solutions to the five-dimensional vacuum Einstein equation. Assuming the existence of two additional commuting rotational Killing vector fields and sphericity of the horizon topology, we show that a black hole with a regular event horizon is uniquely characterized by its mass and a pair of angular momenta.

The hierarchy between the electroweak and Planck scales can be reduced when the extra dimensions are compactified with large volume or with warped geometry, resulting in the fundamental scale of the order of TeV. In such a scenario, one can experimentally study the physics above the Planck scale. We discuss black hole/ring production at future colliders.

We consider the production and decay of TeV sized black holes. After discussing evaluation of the production cross section of higher dimensional rotating black holes and black rings, the master equation for general spin-$s$ fields confined on brane world is derived. For five-dimensional (Randall-Sundrum) black holes, we obtain analytic formulae for the greybody factors in low frequency expansion.

We study theoretical aspects of the rotating black hole production and evaporation in the extra dimension scenarios with TeV scale gravity, within the mass range in which the higher dimensional Kerr solution provides good description. We evaluate the production cross section of black holes taking their angular momenta into account. We find that it becomes larger than the Schwarzschild radius squared, which is conventionally utilized in literature, and our result nicely agrees with the recent numerical study by Yoshino and Nambu within a few percent error for higher dimensional case. In the same approximation to obtain the above result, we find that the production cross section becomes larger for the black hole with larger angular momentum. Second, we derive the generalized Teukolsky equation for spin 0, 1/2 and 1 brane fields in the higher dimensional Kerr geometry and explicitly show that it is separable in any dimensions. For five-dimensional (Randall-Sundrum) black hole, we obtain analytic formulae for the greybody factors in low frequency expansion and we present the power spectra of the Hawking radiation as well as their angular dependence. Phenomenological implications of our result are briefly sketched.

We study theoretical aspects of rotating black hole production and evaporation in extra dimension scenarios with TeV scale gravity, within the mass range in which the higher dimensional Kerr solution provides a good description. We evaluate the production cross section of black holes, taking their angular momenta into account. We find that it becomes larger than the Schwarzschild radius squared, which is conventionally utilized in the literature, and our result nicely agrees with the recent numerical study by Yoshino and Nambu within a few percent error for the higher dimensional case. In the same approximation used to obtain the above result, we find that the production cross section becomes larger for a black hole with larger angular momentum. Second, we derive the generalized Teukolsky equation for spin 0, 1/2, and 1 brane fields in higher dimensional Kerr geometry and explicitly show that it is separable in any dimensions. For a five-dimensional (Randall-Sundrum) black hole, we obtain analytic formulas for the greybody factors in the low frequency expansion and we present the power spectra of the Hawking radiation as well as their angular dependence. The phenomenological implications of our results are briefly sketched.

We discuss the gravitationally interacting system of a thick domain wall and a black hole. We numerically solve the scalar field equation in the Schwarzschild spacetime and obtain a sequence of static axi-symmetric solutions representing thick domain walls. We find that, for the walls near the horizon, the Nambu--Goto approximation is no longer valid.