Ar(n) · neutron relative atomic mass

중성자의 상대 원자 질량

Takeaway

The relative standard uncertainty fell by a factor of about 250 from the 1969 to the 2022 edition (9.9×10⁻⁸ → 4.0×10⁻¹⁰): the error bars narrowed that much.
Of 9 earlier editions with a measured value, 2 have the 2022 value outside ±1σ (the error bar) and 2 outside ±2σ (the bar doubled); the normal expectation is about 1 in 3 and 1 in 22.
The largest move between editions came in 1973→1986, at 2.7 times the combined standard uncertainty of the two editions (|z| = 2.7).

Value ±1σ by edition2022

Relative deviation from the 2022 value (symmetric-log axis). Open circles: the error bar does not reach the 2022 value. Squares: exact.

Editionyear of the recommended values (data cut-off)	As printedexactly as in the source table; digits in parentheses are the standard uncertainty in the last digits	Standard uncertaintyhalf-width of the error bar (±1σ)	Relative standard uncertaintystandard uncertainty ÷ \|value\|: bar width relative to the value	z vs previous editionmove from the previous edition ÷ combined standard uncertainty of the two	z vs 2022(2022 value − this value) ÷ this edition's standard uncertainty	Source locationpage and table of the paper, or file and line of NIST's table
1969	1.00866520(10)	1.0×10⁻⁷	9.9×10⁻⁸		−2.8394	477 table XXXII
1973	1.008665012(37)	3.7×10⁻⁸	3.7×10⁻⁸	−1.7632	−2.5930	718 table 33.1
1986	1.008664904(14)	1.4×10⁻⁸	1.4×10⁻⁸	−2.7300	0.8614	codata86 p.10 table 2
1998	1.008 664 915 78(55)	5.5×10⁻¹⁰	5.5×10⁻¹⁰	0.8408	0.5091	1998 ASCII:230
2002	1.008 664 915 60(55)	5.5×10⁻¹⁰	5.5×10⁻¹⁰	−0.2314	0.8364	2002 ASCII:231
2006	1.008 664 915 97(43)	4.3×10⁻¹⁰	4.3×10⁻¹⁰	0.5300	0.2093	2006 ASCII:232
2010	1.008 664 916 00	4.3×10⁻¹⁰	4.3×10⁻¹⁰	0.0493	0.1395	2010 ASCII:243
2014	1.008 664 915 88	4.9×10⁻¹⁰	4.9×10⁻¹⁰	−0.1841	0.3673	2014 ASCII:243
2018	1.008 664 915 95	4.9×10⁻¹⁰	4.9×10⁻¹⁰	0.1010	0.2245	2018 ASCII:251
2022	1.008 664 916 06	4.0×10⁻¹⁰	4.0×10⁻¹⁰	0.1739		2022 ASCII:252