The fundamental physical constants

The Committee on Data for Science and Technology (CODATA) was established in 1966 as an interdisciplinary committee of the International Council of Scientific Unions (now the International Council for Science). Three years later CODATA created the task group on fundamental constants to periodically provide the scientific and technological communities with a self-consistent set of internationally recommended values for the basic constants and conversion factors of physics and chemistry. Under the auspices of the CODATA task group, we have completed a new least-squares adjustment of those values - termed the 2006 adjustment - that takes into account all relevant data available through 31 December 2006. The tables accompanying this article online (available at http://www.physicstoday.org) give the 2006 CODATA recommended values resulting from that adjustment, except for some specialized x-ray-related quantities and various natural and atomic units. © 2007 American Institute of Physics.