Does the Cosmological Constant really indicate the existence of a Dark Dimension?
Abstract
According to the "dark dimension" (DD) scenario, we might live in a universe with a single compact extra dimension, whose mesoscopic size is dictated by the measured value of the cosmological constant. This scenario is based on swampland conjectures, that lead to the relation between the vacuum energy and the size of the extra dimension ( is the mass scale of a Kaluza-Klein tower), and on the corresponding result from the EFT limit. We show that contains previously missed UV-sensitive terms, whose presence invalidates the widely spread belief (based on existing literature) that the calculation gives automatically the finite result (with no need for fine-tuning). This renders the matching between and a non-trivial issue. We then comment on the necessity to find a mechanism that implements the suppression of the aforementioned UV-sensitive terms. This should finally allow to frame the DD scenario in a self-consistent framework, also in view of its several phenomenological applications based on EFT calculations.
Cite
@article{arxiv.2308.16548,
title = {Does the Cosmological Constant really indicate the existence of a Dark Dimension?},
author = {Carlo Branchina and Vincenzo Branchina and Filippo Contino and Arcangelo Pernace},
journal= {arXiv preprint arXiv:2308.16548},
year = {2024}
}
Comments
18 pages; 1 Appendix. Accepted for publication in International Journal of Geometric Methods in Modern Physics (DOI:10.1142/S0219887824503055)