View source for CODATA Recommended Values of the Fundamental Physical Constants

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The '''CODATA Recommended Values of the Fundamental Physical Constants''' are a set of mutually consistent values for selected [[physical constant]]s, 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 "2010 recommended values", which takes account of all measurements up to 31&nbsp;December 2010: the values were available online from June 2011.<ref>{{CODATA 2010}}.</ref>

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 uncertainty|measurement uncertainties]] (''w''&nbsp;= 1/''u''{{su|p=2|b=r}}), 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 [[Raymond T. Birge|Birge]] in the late 1920s.<ref>{{citation | last = Birge | first = Raymond T. | authorlink = Raymond T. Birge | title = Probable Values of the General Physical Constants | journal = Rev. Mod. Phys. | year = 1929 | volume = 1 | issue = 1 | pages = 1–73 | doi = 10.1103/RevModPhys.1.1}}.</ref><ref>{{citation | last = Birge | first = R. T. | authorlink = Raymond T. Birge | journal = Nuovo Cimento, Suppl. | year = 1957 | volume  = 6 | issue = 1 | pages = 39–67}}.</ref>

==Data pages==
*[[Data:CODATA Recommended Values of the Fundamental Physical Constants 1973|CODATA Recommended Values of the Fundamental Physical Constants 1973]]
*[[Data:CODATA Recommended Values of the Fundamental Physical Constants 1986|CODATA Recommended Values of the Fundamental Physical Constants 1986]]
*[[Data:CODATA Recommended Values of the Fundamental Physical Constants 1998|CODATA Recommended Values of the Fundamental Physical Constants 1998]]
*[[Data:CODATA Recommended Values of the Fundamental Physical Constants 2002|CODATA Recommended Values of the Fundamental Physical Constants 2002]]
*[[Data:CODATA Recommended Values of the Fundamental Physical Constants 2006|CODATA Recommended Values of the Fundamental Physical Constants 2006]]
*[[Data:CODATA Recommended Values of the Fundamental Physical Constants 2010|CODATA Recommended Values of the Fundamental Physical Constants 2010]]

==Notes and references==
===Notes===
{{reflist|group=Note}}

===References===
{{reflist}}

==External links==
*[http://physics.nist.gov/cuu/index.html NIST Reference on Constants, Units, and Uncertainty], with current recommended values
*[http://www.codata.org/taskgroups/TGfundconst/index.html Official site] of the CODATA Task Group on Fundamental Constants

[[Category:Physical constants|*]]

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