Constraining Extra Space Dimensions using Precision Molecular Spectroscopy

TL;DR

This paper uses high-precision molecular spectroscopy of hydrogen molecules to set new constraints on theories involving large extra spatial dimensions, testing physics beyond the Standard Model.

Contribution

It provides the first constraints on extra dimension parameters derived from molecular spectroscopy data within ADD and Randall-Sundrum models.

Findings

Constraints on the compactification scale of extra dimensions.

Limits on brane separation and bulk curvature parameters.

Spectroscopy data improves bounds on extra-dimensional theories.

Abstract

Highly accurate measurements of quantum level energies in molecular systems provide a test ground for new physics, as such effects could manifest themselves as minute shifts in the quantum level structures of atoms and molecules. For the lightest molecular systems, neutral molecular hydrogen (H$_2$, HD and D$_2$) and the molecular hydrogen ions (H$_2^+$, HD$^+$ and D$_2^+$), weak force effects are several orders weaker than current experimental and theoretical results, while contributions of Newtonian gravity and the strong force at the characteristic molecular distance scale of 1 \AA\ can be safely neglected. Comparisons between experiment and QED calculations for these molecular systems can be interpreted in terms of probing large extra space dimensions, under which gravity could become much stronger than in ordinary 3-D space. Under this assumption, using the spectra of H$_2$ we have derived constraints on the compactification scales for extra dimensions within the Arkani-Hamed-Dimopoulos-Dvali (ADD) framework, and constraints on the brane separation and bulk curvature within the Randall-Sundrum (RS-I and RS-II) frameworks.