TGFC – Past Achievements
Task Group Achievements, 2017-18
For the period of 2017 and 2018, the TGFC will have two important deliverables: the 2017 special CODATA adjustment and the 2018 CODATA adjustment of the fundamental constants.
As agreed with the Consultative Committee for Units (CCU), the TGFC will perform a special adjustment in 2017 of all available data for the determination of the values of the defining constants that will be the foundation of the revised International System of Units (SI) that is expected to be adopted in 2018. Due to the timeline for adopting the revised SI, to be considered for the 2017 special CODATA adjustment all relevant input data must be published or accepted for publication by 1 July 2017.
In preparation for the 2017 CODATA Special Adjustment, the TGFC has modified the LSA code and is adding new input data as they become available. Drafts of a summary and a detailed report of the 2017 CODATA special adjustment have been circulated among the TGFC members for input and comments concerning the structure, selection, and treatment of input data. The chair of the TGFC has been in communication with the editors of Metrologia and they are expecting submission of the two completed documents by August 1. It is expected that after critical review, the summary and report will be accepted for publication such that they can be posted and made publicly available before the 23rd CCU meeting 5 – 7 September, 2017.
The next regular CODATA four year cycle adjustment of the fundamental constants will be the 2018 adjustment with a closing date for input data of 31 December, 2018, with the relevant data in publication or preprint form as usual. The results will be made available by 20 May 2019 (World Metrology Day) when the revised SI is to be implemented. The 2018 CODATA adjustment is unique in that it will be the first adjustment of the fundamental constants in the revised SI with much more accurate values for almost all the fundamental constants.
Task Group Activities, 2017-2018
- Closing date for special CODATA adjustment. All relevant input data must have been published or accepted for publication to be considered, 1 July 2017
- Task Group meeting at the BIPM in conjunction with the meeting of the CCU. The TGFC will present the results of the 2017 special CODATA adjustment of the fundamental constants, 4 -7 Sept 2017
- Task Group meeting in conjunction with CPEM 2018 in Paris, France. Discussions will focus on new data for the 2018 CODATA adjustment of the fundamental constants, 7 July 2018
- Closing date for 2018 Codata adjustment of the fundamental constants. All relevant input data must be available in publication or preprint form to be considered, 31 Dec 2018
- The TGFC has recently published the detailed review article on the 2014 CODATA adjustment of the fundamental constants in Reviews of Modern Physics (Rev. Mod. Phys. 88, 035009 (2016) and in the Journal of Physical and Chemical Reference Data (J. Phys. Chem. Ref. Data 45, 043102 (2016)). If the revised SI is adopted in 2018, the 2014 CODATA adjustment of the fundamental constants is unique in that it is the last adjustment in the present SI.
- Using the 2014 values as a template, the TGFC also assisted and advised the Consultative Committee for Units (CCU) during the 22nd meeting of the CCU (15 – 16 June, 2016, BIPM) on the draft resolution 1 adopted by the 105th meeting of the International Committee for Weights and Meaures (CIPM) (October, 2016). In particular, the CIPM agreed with the proposal made by the CCU that the number of digits be kept in the numerical values of the defining constants (i.e. within the relative standard uncertainties from the special 2017 CODATA adjustment of the fundamental constants).
The latest recommended set of constants, called the 2010 LSA, was released early in 2011 on the NIST website (http://pml.nist.gov/cuu/Constants/) and published in 2012 (Mohr et al., Rev. Mod. Phys. 84, 1527 (2012) and Mohr et al., J. Phys. Chem. Ref. Data 41043109 (2012)).
- For 2015
1 – 6 February 2015 – Workshop on the determination of the fundamental constants, Eltville, Germany, Organized by the TGFC.
- For 2014
Task Group updates LSA for CCU/CIPM for CIPM meeting held in November. Update discussed within Task Group by email.
30 August 2014 – Task Group meeting in conjunction with the 2014 Conference on Precision Electromagnetic Measurements, Rio de Janeiro, Brazil. Review new data for upcoming normal 2014 LSA, in particular new watt balance results and isotopic abundance measurements associated with the International Avogadro Project.
3-4 November 2014 – Second 2014 Task Group meeting at the BIPM. Final meeting before closing date for new relevant data for 2014 LSA. Focus on decisions on discrepant data. Special session on data associated with the proton charge radius with invited guest speakers in the research fields of QED, electron-proton scattering, and muonic hydrogen.
Collection of new relevant data, entered into the Fundamental Constants Data Center, in preparation for 2014 LSA
- For 2013
Consultative Committee for Electricity and Magnetism (CCEM) meeting, March 2013. Status report from the Task Group on fundamental constants given by Dr. Barry Wood.
Task Group meeting 10 June, 2013, BIPM. Acceptance of status report to be given to the CCU. Status report focused on relevant data impacting the values and uncertainties of h, e, k and NA since these are the four constants to be defined as exact in the new SI. Results of unofficial LSAs on the values and uncertainties of h, e, k and NA presented.
CCU meeting June, 2013, BIPM. Dr. David Newell represented CODATA and submitted status report. Presentation focused on the history and role of the CODATA TGFC, new data relevant to h, e, k and NA, and discrepant data associated with the proton charge radius.
Selected Working documents
The reports on the meeting of the CODATA Task Group on Fundamental Constants,
from 2000 to 2014 are available in open access here.