E. J. Ahn

Essay: A New Era in High-Energy Physics

In TeV-scale gravity, scattering of particles with center-of-mass energy of the order of a few TeV can lead to the creation of nonperturbative, extended, higher-dimensional gravitational objects: Branes. Neutral or charged, spinning or spinless, Einsteinian or supersymmetric, low-energy branes could dramatically change our picture of high-energy physics. Will we create branes in future particle colliders, observe them from ultra high energy cosmic rays, and discover them to be dark matter?

Uncertainties in limits on TeV-gravity from neutrino-induced showers

Abstract In models with TeV-scale gravity, ultrahigh energy cosmic rays can generate microscopic black holes in the collision with atmospheric and terrestrial nuclei. It has been proposed that stringent bounds on TeV-scale gravity can be obtained from the absence of neutrino cosmic ray showers mediated by black holes. However, uncertainties in the cross section of black hole formation and, most importantly, large uncertainties in the neutrino flux affects these bounds. As long as the cosmic neutrino flux remains unknown, the non-observation of neutrino induced showers implies less stringent limits than present collider limits.

TeV-Scale Gravity: Detecting Black Holes with Cosmic Ray Air Showers

In models of large extra dimensions, gravitational effects may become relevant to particle processes at the TeV scale. In this scenario, extra-dimensional graviton production and graviton exchange events occur at sub-TeV scales, whereas black holes and branes are formed at super-TeV scales. Black holes could soon be detected in particle colliders and in Earth’s atmosphere by cosmic ray telescopes on the ground and in space. The phenomenology of gravitational events is significantly different from that of standard model processes. We review the differences between extensive air showers generated by black holes and standard model interactions.