Methanol as a Sensitive Probe for Spatial and Temporal Variations of the Proton-to-Electron Mass Ratio
Bibliographic record
Abstract
The 6.7 and 12.2 GHz masers, corresponding to the ${5}_{1}\ensuremath{\rightarrow}{6}_{0}{A}^{+}$ and ${2}_{0}\ensuremath{\rightarrow}{3}_{\ensuremath{-}1}E$ transitions in methanol (${\mathrm{CH}}_{3}\mathrm{OH}$), respectively, are among the brightest radio objects in the sky. We present calculations for the sensitivity of these and other transitions in the ground state of methanol to a variation of the proton-to-electron mass ratio. We show that the sensitivity is greatly enhanced due to a cancellation of energies associated with the hindered internal rotation and the overall rotation of the molecule. We find sensitivities of ${K}_{\ensuremath{\mu}}=\ensuremath{-}42$ and ${K}_{\ensuremath{\mu}}=\ensuremath{-}33$, for the ${5}_{1}\ensuremath{\rightarrow}{6}_{0}{A}^{+}$ and ${2}_{0}\ensuremath{\rightarrow}{3}_{\ensuremath{-}1}E$ transitions, respectively. The sensitivities of other transitions in the different isotopologues of methanol range from $\ensuremath{-}88$ to 330. This makes methanol a sensitive probe for spatial and temporal variations of the proton-to-electron mass ratio.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".