Production of black holes and string balls in a two-dimensional split-fermion model

TL;DR

This paper calculates the production cross-sections of black holes and string balls in proton-proton collisions within a two-dimensional split-fermion model, showing reduced likelihood compared to non-split models and explaining the absence of experimental signatures at the LHC.

Contribution

It introduces a two-dimensional split-fermion model to analyze black hole and string ball production, highlighting the impact of brane width and string coupling on cross-sections.

Findings

Cross-sections are smaller in split-fermion models than in non-split models.

Increasing brane width decreases string ball production cross-section significantly.

Black holes are unlikely to be observed at the LHC given current limits.

Abstract

We present cross-sections for the black hole and string ball production in proton-proton collisions in a TeV-scale gravity model with split fermions in two dimensions. The cross-section for black hole and string ball production in the split-fermion model is smaller than in the non-split-fermion model. The drop of the cross-section for the string ball production can be one to two orders of magnitude with the increase of the width of the brane from $L=0$ to 15 $\text{TeV}^{-1}$. The cross-section for string ball production in two-dimensional split fermion model reduces more in comparison to black holes. Black holes are quite hard to be observed at the LHC. In fact, taking into account the current experimental limits on the fundamental Planck scale, black holes cannot be produced at the LHC. Cross-section for string ball production depends significantly on string coupling constant, making it very model dependent. We investigate the range of values of string coupling constant from 0.02 to 0.4. There has been no evidence for production of string balls at $\sqrt{s}=8$ TeV. A two-dimensional split fermion model with a extremely thick brane can account for the absence of signature of string balls for a world with the value of fundamental Planck scale even as low as 1 TeV.