Constraints on mu-variations from the methanol CH3OH thermal lines in the Galaxy at galactocentric distances of 1.5 < D GC < 13 kpc

arXiv:2609.03431 · astro-ph.GA, hep-ex · Submitted 2026-09-03 · Read on arXiv

astro-ph.GA, hep-ex

Submitted: 2026-09-03

Updated: 2026-09-03

Comments: 19 pages, 1 figure, 4 tables; accepted for publication in JETP Letters

License: http://creativecommons.org/licenses/by/4.0/

The gist: In this study, constraints are set on hypothetical variations of the fundamental physical constant mu = m e/m p - the electron-to-proton mass ratio - based on thermal emission lines of E-methanol

Terminology

Abstract

In this study, constraints are set on hypothetical variations of the fundamental physical constant mu = m e/m p - the electron-to-proton mass ratio - based on thermal emission lines of E-methanol (CH3OH) in the 216-220 GHz frequency range. Molecular spectra toward seven massive clouds located across a wide range of galactocentric distances (1.5 < D GC < 13 kpc) have been analyzed. The obtained weighted mean value <Delta mu/mu> = (0.5+/-0.5)*10(-7) does not indicate statistically significant changes in mu at the 1 sigma confidence level of 5*10(-8), which is in good agreement with previously established upper limits in a number of molecular clouds in the Galactic disk.

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