#### ${{\mathit e}}$ MASS

The mass is known more precisely in u (atomic mass units) than in MeV. The conversion is: 1 u = 931.494 102 42(28) MeV/c${}^{2}$ (2018 CODATA value, TIESINGA 2021 ). The conversion error dominates the uncertainty of the masses given below.

VALUE (MeV) DOCUMENT ID TECN  COMMENT
$0.51099895000$ $\pm0.00000000015$
 2021
RVUE 2018 CODATA value
• • We do not use the following data for averages, fits, limits, etc. • •
$0.5109989461$ $\pm0.0000000031$
 2016
RVUE 2014 CODATA value
$0.510998928$ $\pm0.000000011$
 2012
RVUE 2010 CODATA value
$0.510998910$ $\pm0.000000013$
 2008
RVUE 2006 CODATA value
$0.510998918$ $\pm0.000000044$
 2005
RVUE 2002 CODATA value
$0.510998901$ $\pm0.000000020$ 1, 2
 2002
CNTR Penning trap
$0.510998902$ $\pm0.000000021$
 1999
RVUE 1998 CODATA value
$0.510998903$ $\pm0.000000020$ 1, 3
 1995
CNTR Penning trap
$0.510998895$ $\pm0.000000024$ 1
 1987
RVUE 1986 CODATA value
$0.5110034$ $\pm0.0000014$
 1973
RVUE 1973 CODATA value
 1 Converted to MeV using the 1998 CODATA value of the conversion constant, $931.494013$ $\pm0.000037$ MeV/u.
 2 BEIER 2002 compares Larmor frequency of the electron bound in a ${}^{12}\mathrm {C}{}^{5+}$ ion with the cyclotron frequency of a single trapped ${}^{12}\mathrm {C}{}^{5+}$ ion.
 3 FARNHAM 1995 compares cyclotron frequency of trapped electrons with that of a single trapped ${}^{12}\mathrm {C}{}^{6+}$ ion.
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
 BEIER 2002
PRL 88 011603 New Determination of the Electron's Mass
 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
 FARNHAM 1995
PRL 75 3598 Determination of the Electron's Atomic Mass and the Proton/Electron Mass Ratio via Penning Trap Mass Spectroscopy
 COHEN 1987
RMP 59 1121 CODATA Fundamental Physical Constants 1986 Adjustments
 COHEN 1973
JPCRD 2 664 Comment{CODATA}: The 1973 Least Squares Adjustment of the Fundamental Constants