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Cold Molecule Spectroscopy for Constraining the Evolution of the Fine Structure Constant

Eric R. Hudson·H. J. Lewandowski·Brian C. Sawyer·Jun Ye
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Abstract

We report precise measurements of ground-state, $λ$-doublet microwave transitions in the hydroxyl radical molecule (OH). Utilizing slow, cold molecules produced by a Stark decelerator we have improved over the precision of the previous best measurement by twenty-five-fold for the F' = 2 $\to$ F = 2 transition, yielding (1 667 358 996 $\pm$ 4) Hz, and by ten-fold for the F' = 1 $\to$ F = 1 transition, yielding (1 665 401 803 $\pm$ 12) Hz. Comparing these laboratory frequencies to those from OH megamasers in interstellar space will allow a sensitivity of 1 ppm for $Δα/α$ over $\sim$$10^{10}$ years.

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Eric R. Hudson, H. J. Lewandowski, Brian C. Sawyer, Jun Ye. 2006-01-17. Cold Molecule Spectroscopy for Constraining the Evolution of the Fine Structure Constant. https://doi.org/10.1103/physrevlett.96.143004

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