Ar(α) · alpha particle relative atomic mass

알파 입자의 상대 원자 질량

Takeaway

The relative standard uncertainty fell by a factor of about 16 from the 1998 to the 2022 edition (2.5×10⁻¹⁰ → 1.5×10⁻¹¹): the error bars narrowed that much.
Of 6 earlier editions with a measured value, 1 has the 2022 value outside ±1σ (the error bar) and 1 outside ±2σ (the bar doubled); the normal expectation is about 1 in 3 and 1 in 22.
The largest move between editions came in 1998→2002, at 4.4 times the combined standard uncertainty of the two editions (|z| = 4.4).

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
1998	4.001 506 1747(10)	1.0×10⁻⁹	2.5×10⁻¹⁰		4.4290	1998 ASCII:14
2002	4.001 506 179 149(56)	5.6×10⁻¹¹	1.4×10⁻¹¹	4.4420	−0.3571	2002 ASCII:14
2006	4.001 506 179 127(62)	6.2×10⁻¹¹	1.5×10⁻¹¹	−0.2633	0.0323	2006 ASCII:14
2010	4.001 506 179 125	6.2×10⁻¹¹	1.5×10⁻¹¹	−0.0228	0.0645	2010 ASCII:16
2014	4.001 506 179 127	6.3×10⁻¹¹	1.6×10⁻¹¹	0.0226	0.0317	2014 ASCII:16
2018	4.001 506 179 127	6.3×10⁻¹¹	1.6×10⁻¹¹	0.0000	0.0317	2018 ASCII:16
2022	4.001 506 179 129	6.2×10⁻¹¹	1.5×10⁻¹¹	0.0226		2022 ASCII:16