Differential Measurement of m_e/m_p: 3 mm Methanol Lines Toward Sagittarius B2(N) and (M) Molecular Clouds

Differential measurement of the fundamental physical constant mu = m_e/m_p (the electron-to-proton mass ratio) toward two sources located near the Galactic center – the Sagittarius (Sgr) B2(N) and (M) molecular clouds – show a lower mu compared to its terrestrial value.

Based on methanol (CH₃OH) emission lines from the frequency range 80-112 GHz (IRAM 30-m telescope archival data), the calculated difference (Delta mu)/mu = (mu_obs – mu_lab)/mu_lab is equal to (-3.0 +/- 0.6)*10^(-7) (1 sigma C.L.) in the whole cloud SgrB2.

The revealed 5 sigma signal in mu-variations agrees within the margin of error with the recently obtained result based on methanol emission lines from the higher frequency range 542-543 GHz (Herschel space telescope archival data) for SgrB2(N): (Delta mu)/mu = (-4.2 +/- 0.7)*10^(-7).

J. S. Vorotyntseva, S. A. Levshakov, C. Henkel

Comments: 12 pages, 3 tables, 3 figures, submitted to Phys.Rev.D
Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Cite as: arXiv:2506.04258 [astro-ph.GA] (or arXiv:2506.04258v1 [astro-ph.GA] for this version)
https://doi.org/10.48550/arXiv.2506.04258
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Submission history
From: Julia Vorotyntseva
[v1] Mon, 2 Jun 2025 16:46:48 UTC (577 KB)
https://arxiv.org/abs/2506.04258
Astrobiology, Astrochemistry,