Black Holes at the LHC

TL;DR

The work investigates the possibility of producing miniature black holes at the LHC within scenarios of Large or Warped Extra Dimensions, and the subsequent Hawking-radiation signatures on the brane and in the bulk. It develops formation criteria, BH property estimates, and detailed spectra incorporating greybody factors, spin, and angular momentum across Schwarzschild and spin-down phases, including Schwarzschild–de Sitter generalizations. The study assesses how the emitted spectra encode the number of extra dimensions $n$, the fundamental Planck scale $M_*$, and the cosmological constant, and outlines experimental strategies and event generators to extract these parameters from collider data. If realized, BH production would provide a direct probe of extra dimensions, with observable high-energy, high-multiplicity events and distinctive missing-energy patterns shaping search strategies at the LHC.

Abstract

In these two lectures, we will address the topic of the creation of small black holes during particle collisions in a ground-based accelerator, such as LHC, in the context of a higher-dimensional theory. We will cover the main assumptions, criteria and estimates for their creation, and we will discuss their properties after their formation. The most important observable effect associated with their creation is likely to be the emission of Hawking radiation during their evaporation process. After presenting the mathematical formalism for its study, we will review the current results for the emission of particles both on the brane and in the bulk. We will finish with a discussion of the methodology that will be used to study these spectra, and the observable signatures that will help us identify the black-hole events.

Figures (14)

• Figure 1: (a) A 3-brane embedded in a $(4+n)$-dimensional flat spacetime. (b) Two 3-branes embedded in a 5-dimensional Anti de Sitter spacetime.
• Figure 2: Two Aichelburg-Sexl shock waves propagating at opposite directions. The two shock waves collide at $u=v=0$ and, if a closed trapped surface or an apparent horizon is formed, a black hole has been created.
• Figure 3: Absorption cross-section for brane-localised fermions evaluated analytically (left plot), and numerically (right plot).
• Figure 4: Absorption cross-section for brane-localised scalars (left plot) and gauge bosons (right plot).
• Figure 5: Hawking radiation energy emission rates for brane-localised fermions, for $n=0,1,2,4$ and $6$ (from bottom to top).