m_μ/mₑ · muon-electron mass ratio

뮤온-전자 질량비

Takeaway

The relative standard uncertainty fell by a factor of about 102 from the 1973 to the 2022 edition (2.3×10⁻⁶ → 2.2×10⁻⁸): the error bars narrowed that much.
Of 8 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 2.2 times the combined standard uncertainty of the two editions (|z| = 2.2).

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
1973	206.76865(47)	4.7×10⁻⁴	2.3×10⁻⁶		−0.7815	719 table 33.1
1986	206.768262(30)	3.0×10⁻⁵	1.5×10⁻⁷	−0.8239	0.6900	codata86 p.9 table 2
1998	206.768 2657(63)	6.3×10⁻⁶	3.0×10⁻⁸	0.1207	2.6984	1998 ASCII:204
2002	206.768 2838(54)	5.4×10⁻⁶	2.6×10⁻⁸	2.1814	−0.2037	2002 ASCII:205
2006	206.768 2823(52)	5.2×10⁻⁶	2.5×10⁻⁸	−0.2001	0.0769	2006 ASCII:206
2010	206.768 2843	5.2×10⁻⁶	2.5×10⁻⁸	0.2720	−0.3077	2010 ASCII:205
2014	206.768 2826	4.6×10⁻⁶	2.2×10⁻⁸	−0.2449	0.0217	2014 ASCII:205
2018	206.768 2830	4.6×10⁻⁶	2.2×10⁻⁸	0.0615	−0.0652	2018 ASCII:214
2022	206.768 2827	4.6×10⁻⁶	2.2×10⁻⁸	−0.0461		2022 ASCII:215