Torsion in Extra Dimensions and One-Loop Observables

TL;DR

This paper explores how torsion in extra-dimensional gravity theories leads to four-fermion contact interactions that can influence low-energy observables, with precision measurements constraining the fundamental gravity scale.

Contribution

It derives an effective four-dimensional theory with contact operators from torsion in extra dimensions and calculates their impact on observables at one-loop level.

Findings

Existing Z boson decay data set stringent limits on the fundamental gravity scale.

Derived bounds are more restrictive than previous constraints in the literature.

The study links extra-dimensional torsion effects to measurable low-energy phenomena.

Abstract

We study gravity with torsion in extra dimensions and derive an effective four-dimensional theory containing four-fermion contact operators at the fundamental scale of quantum gravity in the TeV range. These operators may have an impact on the low-energy observables and can manifest themselves or can be constrained in precision measurements. We calculate possible contributions of these operators to some observables at the one-loop level. We show that the existing precision data on the lepton decay mode of Z boson set limits on the fundamental scale of the gravity and compactification radius, which are more stringent than the limits previously derived in the literature.