Signatures of Large Extra Dimensions

Abstract

String theory suggests modifications of our spacetime such as extra dimensions and the existence of a mininal length scale. In models with addidional dimensions, the Planck scale can be lowered to values accessible by future colliders. Effective theories which extend beyond the standart-model by including extra dimensions and a minimal length allow computation of observables and can be used to make testable predictions. Expected effects that arise within these models are the production of gravitons and black holes. Furthermore, the Plancklength is a lower bound to the possible resolution of spacetime which might be reached soon. This is a summary of a talk given at the NATO Advanced Study Institute in Kemer, Turkey, Oct. 2003. IntroductionThe standard model (SM) of particle physics yields an extremely precise theory for the electroweak and strong interaction. It allowed us to improve our view of nature in many ways but leaves us with several unsolved problems. E.g. we still have to understand the large number of free parameters in the SM, the question of the fermion families, the mechanism of electroweak symmetry breaking, CP violation, and of course the puzzle of quantum gravity.Gravity, if it is quantized as a spin-2 field in the canonical way, is nonrenormizable. The only reason why the SM yields such high accuracy without concerning gravity is that gravity is much weaker than the other interactions. The effects of quantum gravity get as important as the effects of the SM only at the so-called Planck-scale which is reached at energies near the Planck-mass of m p ≈ 10 16 TeV or at distances near the Planck-length l p ≈ 10 −20 fm, resp. This comparable weakness of the gravitational interaction, also known als the "hierarchy-problem", is another yet unexplained fact which singles out gravity and has to be understood for achieving a successful unifying theory.

Signatures for Black Hole Production From Hadronic Observables at the Large Hadron Collider

“…A suppression of the backward peak is observed for the BH events and is seen to depend on the kinematical region used. Another possible signature is the direct detection of BH relics which are BHs left over at the end of the Hawking decay of mass near the higher-dimensional Planck Mass (∼ 1 TeV) which may be stable 16,17,18 . A preliminary study of the ability of ALICE to detect charged BH relics of 2 TeV mass is shown in Figure 8.…”

TeV mini black hole decay at future colliders

“…A promising realization of these ideas is represented by "TeV-Scale Gravity" where it is possible to introduce a unification scale, M * , as low as some TeV ( [1], [2]). If these theoretical models are correct new exciting phenomenology ( [3], [4]) is going to be observed at future colliders, as the physics of unified interactions, including quantum gravity, will become accessible. No doubts, the most spectacular expected event is a mini black hole production and decay [5].…”