Mass hierarchy and localization of gravity in extra time

TL;DR

This paper explores a modified Randall-Sundrum model with a time-like extra dimension, addressing the hierarchy problem and cosmological expansion, while discussing phenomenological implications of tachyonic Kaluza-Klein graviton states.

Contribution

It introduces a novel Randall-Sundrum scenario with a time-like extra dimension, reconciling the hierarchy problem with correct cosmological expansion.

Findings

Hierarchy problem addressed via time-like extra dimension

Cosmological expansion consistent with observations

Discussion of tachyonic Kaluza-Klein graviton states

Abstract

We consider Randall-Sundrum model with localized gravity, replacing the extra compact space-like dimension by a time-like one. In this way the solution to the hierarchy problem can be reconciled with a correct cosmological expansion of the visible universe, just as a trivial result of the sign flip of cosmological constants in the bulk and on the 3-branes relative to the case of extra space-like dimension. Some phenomenological aspects of the proposed scenario related to the tachyonic nature of Kaluza-Klein states of graviton are also discussed.