#### ${{\mathit \mu}}$ MASS (atomic mass units u)

The muon's mass is obtained from the muon-electron mass ratio as determined from the measurement of Zeeman transition frequencies in muonium ( ${{\mathit \mu}^{+}}{{\mathit e}^{-}}$ atom). Since the electron's mass is most accurately known in u, the muon's mass is also most accurately known in u. The conversion factor to MeV has approximately the same relative uncertainty as the mass of the muon in u. In this datablock we give the result in u, and in the following datablock in MeV.

VALUE (u) DOCUMENT ID TECN  COMMENT
$0.1134289259$ $\pm0.0000000025$
 2021
RVUE 2018 CODATA value
• • We do not use the following data for averages, fits, limits, etc. • •
$0.1134289257$ $\pm0.0000000025$
 2016
RVUE 2014 CODATA value
$0.1134289267$ $\pm0.0000000029$
 2012
RVUE 2010 CODATA value
$0.1134289256$ $\pm0.0000000029$
 2008
RVUE 2006 CODATA value
$0.1134289264$ $\pm0.0000000030$
 2005
RVUE 2002 CODATA value
$0.1134289168$ $\pm0.0000000034$ 1
 1999
RVUE 1998 CODATA value
$0.113428913$ $\pm0.000000017$ 2
 1987
RVUE 1986 CODATA value
 1 MOHR 1999 make use of other 1998 CODATA entries below.
 2 COHEN 1987 make use of other 1986 CODATA entries below.
References:
 TIESINGA 2021
RMP 93 025010 CODATA recommended values of the fundamental physical constants: 2018
 MOHR 2016
RMP 88 035009 CODATA Recommended Values of the Fundamental Physical Constants: 2014
 MOHR 2012
RMP 84 1527 CODATA Recommended Values of the Fundamental Physical Constants: 2010
 MOHR 2008
RMP 80 633 CODATA Recomended Values of the Fundamental Physical Constants: 2006
 MOHR 2005
RMP 77 1 NIST Constants
 MOHR 1999
JPCRD 28 1713 CODATA Recommended Values of the Fundamental Physical Constants: 1998;
 Also
RMP 72 351 CODATA Recommended Values of the Fundamental Physical Constants: 1998
 COHEN 1987
RMP 59 1121 CODATA Fundamental Physical Constants 1986 Adjustments