2021/09/01 by Eite Tiesinga, Peter J. Mohr, David B. Newell +1 · 1 citation
Physics and Astronomy · Decision Sciences · Chemistry · #Radioactive Decay and Measurement Techniques #Scientific Measurement and Uncertainty Evaluation #Atomic and Molecular Physics #Avogadro constant #Rydberg constant #Planck constant #Physics #Physical constant #Charge radius #Fine-structure constant #Constant (computer programming) #Dimensionless quantity #Gravitational constant #Chemistry #Quantum mechanics #Theoretical physics #Proton #Gravitation #Electron #Quantum
paper · doi:10.1063/5.0064853
openalex publication_date 2021/09/01 · openalex created_date 2022/02/08 · openalex updated_date 2026/07/28
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.