We report the 2018 self-consistent values of constants and conversion factors of physics and chemistry recommended by the Committee on Data of the International Science Council. The recommended values can also be found at physics.nist.gov/constants. The values are based on a least-squares adjustment that takes into account all theoretical and experimental data available through 31 December 2018. A discussion of the major improvements as well as inconsistencies within the data is given. The former include a decrease in the uncertainty of the dimensionless fine-structure constant and a nearly two orders of magnitude improvement of particle masses expressed in units of kg due to the transition to the revised International System of Units (SI) with an exact value for the Planck constant. Further, because the elementary charge, Boltzmann constant, and Avogadro constant also have exact values in the revised SI, many other constants are either exact or have significantly reduced uncertainties. Inconsistencies remain for the gravitational constant and the muon magnetic-moment anomaly. The proton charge radius puzzle has been partially resolved by improved measurements of hydrogen energy levels.
CODATA Recommended Values of the Fundamental Physical Constants: 2018*
This review is being published simultaneously by Reviews of Modern Physics.
This report was prepared by the authors under the auspices of the CODATA Task Group on Fundamental Constants. The members of the task group are:
F. Bielsa, Bureau International des Poids et Mesures
K. Fujii, National Metrology Institute of Japan, Japan
S. G. Karshenboim, Pulkovo Observatory, Russian Federation and Max-Planck-Institut für Quantenoptik, Germany
H. Margolis, National Physical Laboratory, United Kingdom
P. J. Mohr, National Institute of Standards and Technology, United States of America
D. B. Newell, National Institute of Standards and Technology, United States of America
F. Nez, Laboratoire Kastler-Brossel, France
R. Pohl, Johannes Gutenberg-Universität Mainz, Germany
K. Pachucki, University of Warsaw, Poland
J. Qu, National Institute of Metrology of China, China
A. Surzhykov, Physikalisch-Technische Bundesanstalt, Germany
E. Tiesinga, National Institute of Standards and Technology, United States of America
M. Wang, Institute of Modern Physics, Chinese Academy of Sciences, China
B. M. Wood, National Research Council, Canada
Eite Tiesinga, Peter J. Mohr, David B. Newell, Barry N. Taylor; CODATA Recommended Values of the Fundamental Physical Constants: 2018. J. Phys. Chem. Ref. Data 1 September 2021; 50 (3): 033105. https://doi.org/10.1063/5.0064853
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