${{\boldsymbol n}}$ MASS (MeV) INSPIRE search

The mass is known much more precisely in u (atomic mass units) than in MeV. The conversion from u to MeV, 1 u = 931.494$~$0054(57)) MeV/$\mathit c{}^{2}$ (MOHR 2016 , the 2014 CODATA value), involves the relatively poorly known electronic charge.

VALUE (MeV)

DOCUMENT ID

TECN

COMMENT

$939.5654133$ $\pm0.0000058$

MOHR

2016

RVUE

2014 CODATA value

• • • We do not use the following data for averages, fits, limits, etc. • • •

$939.565379$ $\pm0.000021$

MOHR

2012

RVUE

2010 CODATA value

$939.565346$ $\pm0.000023$

MOHR

2008

RVUE

2006 CODATA value

$939.565360$ $\pm0.000081$

MOHR

2005

RVUE

2002 CODATA value

$939.565331$ $\pm0.000037$

KESSLER

1999

SPEC

${{\mathit n}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit d}}{{\mathit \gamma}}$

$939.565330$ $\pm0.000038$

MOHR

1999

RVUE

1998 CODATA value

$939.56565$ $\pm0.00028$

² ^{, 3}

DIFILIPPO

1994

TRAP

Penning trap

$939.56563$ $\pm0.00028$

COHEN

1987

RVUE

1986 CODATA value

$939.56564$ $\pm0.00028$

⁴ ^{, 3}

GREENE

1986

SPEC

${{\mathit n}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit d}}{{\mathit \gamma}}$

$939.5731$ $\pm0.0027$

COHEN

1973

RVUE

1973 CODATA value

¹ We use the 1998 CODATA u-to-MeV conversion factor (see the heading above) to get this mass in MeV from the much more precisely measured KESSLER 1999 value of $1.00866491637$ $\pm0.00000000082~$u.

² The mass is known much more precisely in u: $\mathit m$ = $1.0086649235$ $\pm0.0000000023$ u. We use the 1986 CODATA conversion factor to get the mass in MeV.

³ These determinations are not independent of the ${\mathit m}_{{{\mathit n}}}–{\mathit m}_{{{\mathit p}}}$ measurements below.

⁴ The mass is known much more precisely in u: $\mathit m$ = $1.008664919$ $\pm0.000000014$ u.

References:

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