${{\mathit n}}$ ELECTRIC DIPOLE MOMENT

INSPIRE   PDGID:
S017EDM
A nonzero value is forbidden by both $\mathit T$ invariance and $\mathit P$ invariance. A number of early results have been omitted. See RAMSEY 1990, GOLUB 1994, and LAMOREAUX 2009 for reviews.

The results are upper limits on $\vert {{\mathit d}_{{{n}}}}\vert $.
VALUE ($ 10^{-25} $ $\mathit e~$cm) CL% DOCUMENT ID TECN  COMMENT
$\bf{<0.18}$ 90 1
ABEL
2020
MRS UCN
• • We do not use the following data for averages, fits, limits, etc. • •
$<0.22$ 95 2
SAHOO
2017
${}^{199}\mathrm {Hg}$ atom EDM + theory
$<0.16$ 95
GRANER
2016
MRS ${}^{199}\mathrm {Hg}$ atom EDM + theory
$<0.30$ 90 3
PENDLEBURY
2015
MRS Supersedes BAKER 2006
$<0.55$ 90
SEREBROV
2015
MRS UCN's, h${{\mathit \nu}}$ = 2${{\mathit \mu}_{{{n}}}}$B $\pm$ 2${{\mathit d}_{{{n}}}}$E
$<0.55$ 90 4
SEREBROV
2014
MRS See SEREBROV 2015
$<0.29$ 90 5
BAKER
2006
MRS See PENDLEBURY 2015
$<0.63$ 90 6
HARRIS
1999
MRS ${{\mathit d}}$ = ($-0.1$ $\pm0.36$) $ \times 10^{-25}$
$<0.97$ 90
ALTAREV
1996
MRS See SEREBROV 2014
$<1.1$ 95
ALTAREV
1992
MRS See ALTAREV 1996
$<1.2$ 95
SMITH
1990
MRS See HARRIS 1999
$<2.6$ 95
ALTAREV
1986
MRS ${{\mathit d}}$ = ($-1.4$ $\pm0.6$) $ \times 10^{-25}$
$0.3$ $\pm4.8$
PENDLEBURY
1984
MRS Ultracold neutrons
$<6$ 90
ALTAREV
1981
MRS ${{\mathit d}}$ = ($2.1$ $\pm2.4$) $ \times 10^{-25}$
$<16$ 90
ALTAREV
1979
MRS ${{\mathit d}}$ = ($4.0$ $\pm7.5$) $ \times 10^{-25}$
1  ABEL 2020 reports ${{\mathit d}}$ = ($0.0$ $\pm1.1$ $\pm0.2$) $ \times 10^{-26}{{\mathit e}}~$cm value corresponding to the listed limit.
2  SAHOO 2017 develops theory to calculate this limit from the measured limit by GRANER 2016 of the ${}^{199}\mathrm {Hg}$ atom EDM.
3  PENDLEBURY 2015 reports ${{\mathit d}}$ = ($-0.21$ $\pm1.82$) $ \times 10^{-26}{{\mathit e}}~$cm value corresponding to the listed limit.
4  SEREBROV 2014 includes the data of ALTAREV 1996.
5  LAMOREAUX 2007 faults BAKER 2006 for not including in the estimate of systematic error an effect due to the Earth's rotation. BAKER 2007 replies (1) that the effect was included implicitly in the analysis and (2) that further analysis confirms that the BAKER 2006 limit is correct as is. See also SILENKO 2007.
6  This HARRIS 1999 result includes the result of SMITH 1990. However, the averaging of the results of these two experiments has been criticized by LAMOREAUX 2000.
Conservation Laws:
TIME REVERSAL ($\mathit T$) INVARIANCE
$\mathit CP$ INVARIANCE
PARITY ($\mathit P$) INVARIANCE
References