Recommended Values of the Fundamental Physical Constants: A Status Report
Barry N Taylor1, E Richard Cohen2
1National Institute of Standards and Technology, Gaithersburg, MD 20899.
Summary
New physical constant data offers 5-7x smaller uncertainties, though values remain largely consistent. Key advances in Planck constant, fine-structure constant, and molar gas constant require further validation before the next adjustment.
Area of Science:
- Metrology
- Fundamental Physics
- Quantum Mechanics
Background:
- The 1986 Committee on Data for Science and Technology (CODATA) least-squares adjustment established recommended values for fundamental physical constants.
- Advances in experimental techniques and theoretical understanding have since generated new data relevant to these constants.
Purpose of the Study:
- To review significant advancements in fundamental physical constants since the 1986 CODATA adjustment.
- To assess the impact of new data on the 1986 recommended values and inform the upcoming adjustment.
Main Methods:
- Analysis of newly available experimental and theoretical results for key physical constants.
- Evaluation of the impact of dominant new measurements on the overall uncertainty and values of constants.
Main Results:
- New results yield uncertainties 5 to 7 times smaller than those in the 1986 CODATA values.
- Observed changes in constant values are generally less than twice the 1986 standard deviation, indicating limited significance.
- Dominant contributions come from new measurements of the Planck constant, fine-structure constant, and molar gas constant.
Conclusions:
- The 1986 CODATA values remain the recommended set pending further corroboration of dominant new data.
- Additional high-precision results are needed to validate recent advances before the next least-squares adjustment.
- Future adjustments will benefit from improved accuracy and reduced uncertainties in fundamental physical constants.
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