2 τ mass

A total of 10 τ mass measurements are averaged. The fit has χ²/d.o.f. = 8.2/9, corresponding to a confidence level CL = 51%. We include recent measurements by Belle II [6] and KEDR [7], which were not included in the 2022 edition and 2023 update of the Review of Particle Physics [8]. Table 1 and Figure 1 report the experimental inputs and the calculated average, which are also available at [9].

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Table 1: τ mass measurements and their average.

τ mass [MeV]	Experiment	Reference
1776.30 ± 2.40 ± 1.40	ARGUS	[10]
1776.68 ± 0.12 ± 0.41	BABAR	[11]
1776.61 ± 0.13 ± 0.35	Belle	[12]
1777.09 ± 0.08 ± 0.11	Belle II	[6]
1776.96 −0.21+0.18 −0.17+0.25	BES	[13]
1776.91 ± 0.12 −0.13+0.10	BES3	[14]
1778.20 ± 0.80 ± 1.20	CLEO	[15]
1783.00 −4.00+3.00 ± 0.00	DELCO	[16]
1776.69 −0.19+0.17 ± 0.15	KEDR	[7]
1775.10 ± 1.60 ± 1.00	OPAL	[17]
1776.94 ± 0.09	HFLAV average

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PNG format	PDF format

Figure 1: τ mass measurements and their average.

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