CODATA Recommended Values of the Fundamental Physical Constants
The CODATA Recommended Values of the Fundamental Physical Constants are a set of mutually consistent values for selected physical constants, calculated under the auspices of the CODATA Task Group on Fundamental Constants. Since 1998, calculations have been carried out every four years by the U.S. National Institute for Standards and Technology (NIST), and the values are diffused via the NIST website as well as by publication in the printed scientific literature. The most current set is the "2006 recommended values", which takes account of all measurements up to 31 December 2006: the values were available online from March 2007, and the full description was published in 2008.[1] The next set of values is expected to be available in early 2011.
The calculation is a least squares adjustment of the experimental values to obtain a self-consistent set. The input values are weighted according to their relative measurement uncertainties (w = 1/u2r), so that more precise values have a higher effect on the final result than less precise experiments.
History
The first analysis of the values of physical constants was carried out by Birge in the late 1920s.[2][3]
Notes and references
Notes
References
- ↑ Mohr, Peter J.; Taylor, Barry N.; Newell, David B. CODATA Recommended Values of the Fundamental Physical Constants: 2006. Rev. Mod. Phys. 2008, 80 (2), 633–730. doi:10.1103/RevModPhys.80.633, <http://physics.nist.gov/cuu/Constants/codata.pdf>.
- ↑ Birge, Raymond T. Probable Values of the General Physical Constants. Rev. Mod. Phys. 1929, 1 (1), 1–73. DOI: 10.1103/RevModPhys.1.1.
- ↑ Birge, R. T. Nuovo Cimento, Suppl. 1957, 6 (1), 39–67.
External links
- NIST Reference on Constants, Units, and Uncertainty, with current recommended values
- Official site of the CODATA Task Group on Fundamental Constants
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