Will we observe black holes at LHC?

The generalized uncertainty principle, motivated by string theory and non-commutative quantum mechanics, suggests significant modifications to the Hawking temperature and evaporation process of black holes. For extra-dimensional gravity with Planck scale O(TeV), this leads to important changes in the formation and detection of black holes at the the Large Hadron Collider. The number of particles produced in Hawking evaporation decreases substantially. The evaporation ends when the black hole mass is Planck scale, leaving a remnant and a consequent missing energy of order TeV. Furthermore, the minimum energy for black hole formation in collisions is increased, and could even be increased to such an extent that no black holes are formed at LHC energies.Comment: 5 pages, 2 figures. Minor changes to match version to appear in Class. Quant. Gra

Origami World

We paste together patches of $AdS_6$ to find solutions which describe two 4-branes intersecting on a 3-brane with non-zero tension. We construct explicitly brane arrays with Minkowski, de Sitter and Anti-de Sitter geometries intrinsic to the 3-brane, and describe how to generalize these solutions to the case of $AdS_{4+n}$, $n>2$, where $n$ $n+2$-branes intersect on a 3-brane. The Minkowski and de Sitter solutions localize gravity to the intersection, leading to 4D Newtonian gravity at large distances. We show this explicitly in the case of Minkowski origami by finding the zero-mode graviton, and computing the couplings of the bulk gravitons to the matter on the intersection. In de Sitter case, this follows from the finiteness of the bulk volume. The effective 4D Planck scale depends on the square of the fundamental 6D Planck scale, the $AdS_6$ radius and the angles between the 4-branes and the radial $AdS$ direction, and for the Minkowski origami it is $M_4{}^2 = {2/3} \Bigl(\tan \alpha_1 + \tan \alpha_2 \Bigr) M_*{}^4 L^2$. If $M_* \sim {\rm few} \times TeV$ this may account for the Planck-electroweak hierarchy even if $L \sim 10^{-4} {\rm m}$, with a possibility for sub-millimeter corrections to the Newton's law. We comment on the early universe cosmology of such models.Comment: plain LaTeX, 23 pages + 2 .eps figure