Einstein-Cartan gravity excludes extra dimensions

TL;DR

This paper demonstrates that Einstein-Cartan gravity with extra dimensions predicts an electron size incompatible with experimental limits, challenging certain models of extra dimensions in particle physics.

Contribution

It shows that models like Arkani-Hamed-Dimopoulos-Dvali and Randall-Sundrum are incompatible with Einstein-Cartan theory if spin induces torsion.

Findings

Electron size in Einstein-Cartan with extra dimensions exceeds experimental bounds

Certain extra-dimensional models are ruled out under Einstein-Cartan gravity

Torsion effects from spin alter fundamental particle size predictions

Abstract

We show that the electron in the Riemann-Cartan spacetime with extra dimensions has a finite size that is much larger than the experimental upper limit on its radius. Thus the Arkani-Hamed-Dimopoulos-Dvali and Randall-Sundrum models of the weak/Planck hierarchy in particle physics are not viable if spin produces torsion according to the Einstein-Cartan theory of gravity.