Quantum black holes at the LHC: production and decay mechanisms of non-thermal microscopic black holes in particle collisions

The scale of quantum gravity could be as low as a few TeV in the existence of extra spatial dimensions or if the Planck scale runs fast due to a large number of particles in a hidden sector. One of the most striking features of low-scale quantum gravity models would be the creation of quantum black holes, i.e. non-thermal black holes with masses around a few TeV, in high energy collisions. This thesis deals with the production and decay mechanisms of quantum black holes at current colliders, such as the Large Hadron Collider (LHC). Firstly, a review of models with low-scale gravity is given. We will present an overview of production and decay mechanism of classical and semi-classical black holes, including the Hoop conjecture criterion, closed trapped surfaces and thermal decay via Hawking radiation. We will then introduce a phenomenological approach of black holes, very differently from the (semi-)classical counterparts, which covers a substantially model independent and specifically established field theory, describing the production of quantum black holes. This is done by matching the amplitude of the quantum black hole processes to the extrapolated semi-classical cross section. All possible decay channels and their probabilities are found for quantum black holes with a continuous and discrete mass spectrum, respectively, by considering different symmetry conservation restrictions for a quantum gravitational theory. In conjunction with these branching ratios, we developed a Monte Carlo integration algorithm to determine the cross sections of specific final states. We extended the algorithm to investigate the enhancement of supersymmetric particle production via quantum black hole processes. Studying such objects proves very important, since it provides new possible insights and restrictions on the quantum black hole model and likewise on the low-scale quantum gravity scenarios.