8. International conference on atomic masses and fundamental constants (AMCO-8)

The current recommended values of the fundamental physical constants are base on an adjustment carried out in 1986. Physics, however, has not stood still. New measurements have been reported for the Rydberg constant and the gas constant. Improved calculations and measurements of the electron magnetic moment anomaly, ae have provided an improved value for the fine structure constant α = μ0ce2/2h. The decision to establish uniform international representation of the volts and ohms in terms of the Josephson effect and the quantized Hall resistance, respectively, stimulated new measurements of 2e/h and e/h2. These new data have significantly changed the error-space of the adjustment of the physical constants. In the 1986 adjustments, the one-standard deviation uncertainty in α was 0.045 ppm; the university of Washington measurements of ae and the final results of Kinoshita's 20-year program of numerical evaluation of the eight order QED diagrams yield a new value with an uncertainty of 0.0069 ppm. Combined with the Rydberg constant and the proton-electron mass ratio this means that NΛh = Mpα2c/(2(mp/me)R∞) is defined with an uncertainty of 0.025 ppm