Computational insight into diatomic molecules as probes to measure the variation of the proton-to-electron mass ratio

TL;DR

This study evaluates diatomic molecules as probes for detecting variations in the proton-to-electron mass ratio, emphasizing the importance of molecular properties and observational factors, and identifies promising candidates like CN, CP, SiN, and SiC.

Contribution

The paper provides a detailed analysis of astrophysical diatomic molecules' potential for probing fundamental physics, highlighting factors influencing sensitivity and identifying promising molecular candidates.

Findings

None of the 11 molecules showed enhanced observable transitions.

CN, CP, SiN, and SiC are the most promising molecules.

Further investigation is focused on CN.

Abstract

Astrophysical molecular spectroscopy is an important means of searching for new physics through probing the variation of the proton-to-electron mass ratio, $\mu$. New molecular probes could provide tighter constraints on the variation of $\mu$ and better direction for theories of new physics. Here we summarise our previous paper \citep{19SyMoCu.CN} for astronomers, highlighting the importance of accurate estimates of peak molecular abundance and temperature as well as spectral resolution and sensitivity of telescopes in different regions of the electromagnetic spectrum. Whilst none of the 11 astrophysical diatomic molecules we investigated showed enhanced sensitive rovibronic transitions at observable intensities for astrophysical environments, we have gained a better understanding of the factors that contribute to high sensitivities. From our results, CN, CP, SiN and SiC have shown the most promise of all astrophysical diatomic molecules for further investigation, with further work currently being done on CN.