Asymmetrical large extra dimensions
Joseph Lykken, Satyanarayan Nandi
TL;DR
The paper investigates asymmetrical large extra dimensions with a hierarchy between a millimeter-scale dimension and TeV$^{-1}$-scale dimensions, encoded by $M_P^2 = M_*^{n+2} R^n = M^{n+m+2} R^n r^m$ and the specific $(n,m)=(1,5)$ case where $1/R \\sim 10^{-3}$ eV and $1/r \\sim 1$ TeV. It analyzes astrophysical constraints, showing that SN and diffuse MeV gamma-ray bounds push the relevant scales high, allowing the scenario to evade stringent limits for a single mm dimension, while predicting TeV-scale KK gauge bosons that modify collider phenomenology. The authors highlight smoking-gun collider signatures from KK gluons, including enhanced high-$p_T$ jets, multi-jet final states, and altered top-quark production, which offer concrete tests at the Tevatron and LHC. The work presents a viable, testable alternative to symmetric large extra dimension scenarios, with implications for gauge coupling running and neutrino mass mechanisms.
Abstract
We study scenarios in which there is a hierarchy of two sets of large compactified extra dimensions. One particularly interesting case has a single millimeter size extra dimension and five TeV^{-1} size dimensions. The Standard Model gauge bosons have Kaluza-Klein excitations with respect to one of the TeV scale dimensions. We discuss astrophysical constraints on this scenario, as well as prospects for signals at future high energy colliders.