---
slug: the-proton-that-stayed-small
passed: 2026-10-18
by: the assay line (research/assay-line/claude-1018c/), Claude fixer (claude-opus-5-5) directed by claude-assaying-boyle-1014; source record by a Claude agent (claude-sonnet-5-5), checked by a Claude agent (claude-opus-5-5)
checked: 119
confirmed: 114
wrong: 2             # 0 WRONG + 2 MINOR
unverifiable: 0
observed: 3
stale: 0
---

This was a directed repair pass over the 2 triage items in research/assay-line/claude-1018c/the-proton-that-stayed-small/triage.json, carried out on the working tree at 8bcbe08393 (the checker read the layer at e7c21dfcc4; its full record is research/assay-line/claude-1018c/the-proton-that-stayed-small/N2-claude.md, against the source record N1-sources.json). The checker found nothing WRONG and two MINOR lines. The fixer re-read Crossref for the Rev. Mod. Phys. CODATA 2022 record and the page's JSON-LD, fixed the stale JSON-LD dateModified (and the verifier assertion that pinned it to the publication date), and listed the CODATA publication-date slip because its fix trips the layer's frozen visible-text fingerprint. The claim lines below are the checker's, with the two MINOR lines given their dispositions. No Corrected or Updated line was added: neither item is WRONG or STALE.

## Claims
- CONFIRMED | we find rₚ = 0.84184(67) fm, which differs by 5.0 standard deviations from the CODATA value of 0.8768(69) fm. | https://www.nature.com/articles/nature09250 | [q-pohl-find] abstract (curl with a browser UA reads it; the tool got 190 chars): "we find r p = 0.84184(67) fm, which differs by 5.0 standard deviations from the CODATA value 3 of 0.8768(69) fm." Only the reference numeral 3 and subscript differ, as the page declares
- CONFIRMED | Our result implies that either the Rydberg constant has to be shifted by −110 kHz/c (4.9 standard deviations), or the calculations of the QED effects in atomic hydrogen or muonic hydrogen atoms are insufficient. | https://www.nature.com/articles/nature09250 | [q-pohl-eitheror] abstract, verbatim apart from "kHz/ c" spacing
- CONFIRMED | This comparison tests the (uncorrelated) Doppler shift extrapolation and corrections for the light force, QI and dc-Stark shifts, with the last two of opposite sign for the two transitions. | https://www.nature.com/articles/s41586-026-10124-3 | [q-mais-uncorrelated] verbatim; it is the sentence after the QED comparison that follows equation (6)
- CONFIRMED | Having confirmed the muonic value of rₚ, we now explicitly compare the SM prediction | https://www.nature.com/articles/s41586-026-10124-3 | [q-mais-confirmed] verbatim, first sentence under "Test of the SM prediction"
- CONFIRMED | values of rₚ from recent measurements of atomic hydrogen are partly discrepant with each other and with a more precise value from spectroscopy of muonic hydrogen | https://www.nature.com/articles/s41586-026-10124-3 | [q-mais-discrepant] in the Abstract: "However, values of rp from recent measurements2,3,4,5,6,7 of atomic hydrogen are partly discrepant..."; numerals omitted as declared
- CONFIRMED | The proton radius “puzzle” is not yet solved. | https://physics.nist.gov/cuu/pdf/JPCRD2022CODATA.pdf | [q-codata-puzzle] pdftotext of the NIST PDF, Sec. I.B (Overview), p. 54, 033105-4: "The proton radius “puzzle” is not yet solved." arXiv:2409.03787v1 has "is not yet over"; the page links the JPCRD PDF, whose wording it quotes
- CONFIRMED | A resolution, based on very recent experiments, is stated. The proton radius puzzle is no more. | https://arxiv.org/abs/2604.15546v2 | [q-miller] arXiv abstract, verbatim
- CONFIRMED | Pohl and 31 coauthors, The size of the proton, Nature (2010). | https://api.crossref.org/works/10.1038/nature09250 | [c-pohl-link] Crossref: "The size of the proton", Nature 466(7303) 213-216, 32 authors, so "31 coauthors" is right
- CONFIRMED | R. Pohl et al., The size of the proton. Nature 466, 213-216 (8 July 2010). DOI: 10.1038/nature09250. | https://api.crossref.org/works/10.1038/nature09250 | [c-pohl-datajs] Crossref volume, pages, DOI match; MIT copy prints "Vol 466 / 8 July 2010 / doi:10.1038/nature09250"
- CONFIRMED | Lothar Maisenbacher, Vitaly Wirthl, Arthur Matveev, Alexey Grinin, Randolf Pohl, Theodor W. Hänsch and Thomas Udem, Sub-part-per-trillion test of the Standard Model with atomic hydrogen. Nature 650, 845-851 (11 February 2026). DOI: 10.1038/s41586-026-10124-3. | https://api.crossref.org/works/10.1038/s41586-026-10124-3 | [c-mais-datajs] Crossref: same 7 authors in order, Nature 650, 845-851, published online 2026-02-11
- CONFIRMED | R. G. Bullis, W. L. Tavis, M. R. Weiss, J. Orellana Cisneros, A. J. Cheeseman, U. D. Jentschura and D. C. Yost, Precision Spectroscopy of 2S-nS Transitions in Atomic Hydrogen: A Determination of the Proton Charge Radius. Physical Review Letters 136, 123001 (23 March 2026). DOI: 10.1103/lgl2-6cb8. | https://api.crossref.org/works/10.1103/lgl2-6cb8 | [c-bullis-datajs] Crossref: title and 7 authors match, PRL 136, 123001, issued 2026-03-23
- CONFIRMED | Peter J. Mohr, David B. Newell, Barry N. Taylor and Eite Tiesinga, CODATA recommended values of the fundamental physical constants: 2022. Journal of Physical and Chemical Reference Data 54, 033105 (16 September 2025). DOI: 10.1063/5.0279860. | https://api.crossref.org/works/10.1063/5.0279860 | [c-codata22-datajs] Crossref authors "Peter J. Mohr; David B. Newell; Barry N. Taylor; Eite Tiesinga", JPCRD 54(3) 033105, online 2025-09-16. The tool's DOI MISMATCH ("gives Mohr the initial J.") is a name-parsing false positive: the names are identical
- CONFIRMED | Peter J. Mohr, Barry N. Taylor and David B. Newell, CODATA recommended values of the fundamental physical constants: 2006. Reviews of Modern Physics 80, 633-730 (2008). DOI: 10.1103/RevModPhys.80.633. Values read in arXiv:0801.0028v1. | https://api.crossref.org/works/10.1103/RevModPhys.80.633 | [c-codata06-datajs] Crossref: Mohr, Taylor, Newell, RMP 80, 633-730, 2008-06-06. Tool DOI MISMATCH is the same parsing false positive
- CONFIRMED | Gerald A. Miller, The Proton Radius Puzzle. Specialist review preprint, arXiv:2604.15546v2, revised 25 April 2026. Prepared for Encyclopedia of Nuclear Physics. | https://arxiv.org/abs/2604.15546v2 | [c-miller-datajs] arXiv: "[v2] Sat, 25 Apr 2026", "Prepared for Encyclopedia of Nuclear Physics"
- CONFIRMED | Maisenbacher and colleagues (2026), after equation (6). | https://www.nature.com/articles/s41586-026-10124-3 | [c-mais-after-eq6] the quoted sentence follows equation (6) and the QED comparison sentence
- CONFIRMED | Maisenbacher and colleagues (2026), opening the Standard Model test. | https://www.nature.com/articles/s41586-026-10124-3 | [c-mais-open-sm] the quoted words open the section "Test of the SM prediction"
- CONFIRMED | Maisenbacher and colleagues, equations (4) to (10) and Table 1. | https://www.nature.com/articles/s41586-026-10124-3 | [c-mais-eq4-10] equations (4)-(10) and Table 1 hold every number the page cites them for
- CONFIRMED | CODATA 2022, overview of the 2022 adjustment (section I.B). | https://physics.nist.gov/cuu/pdf/JPCRD2022CODATA.pdf | [c-codata-overview] the quoted sentence is in "B. Overview of the 2022 adjustment" (section I.B), last sentence of the proton-radius paragraph
- CONFIRMED | In 2010 muonic hydrogen put the proton 4.0 per cent smaller than the accepted value, 5.0 standard deviations away. | https://www.nature.com/articles/nature09250 | [f-dek-4pct] (0.8768-0.84184)/0.8768 = 3.99 per cent; 5.0 sigma printed in the abstract
- CONFIRMED | In 2010 a measurement with muons said the proton is smaller than the accepted value, and the most precise later measurements with ordinary hydrogen agreed. | https://www.nature.com/articles/s41586-026-10124-3 | [f-plain-agreed] abstract: 0.8406(15) fm "in excellent agreement with the muonic value"; Bullis 0.8433(31) fm is 0.9 sigma from 0.84060(39)
- CONFIRMED | Replace hydrogen’s electron with a negative muon, a particle about two hundred times heavier. | https://web.mit.edu/OLYMPUS/DOCUMENTS/nature09250.pdf | [f-muon-200] MIT copy p. 213: "The muon is about 200 times heavier than the electron."
- CONFIRMED | The muon orbits far closer to the proton, so the atom becomes far more sensitive to how the proton’s charge is spread. | https://www.nature.com/articles/nature09250 | [f-muon-closer] abstract, as excerpted
- CONFIRMED | The collaboration measured one transition in that atom with a pulsed laser, then inverted a theory formula to get a root-mean-square charge radius. | https://web.mit.edu/OLYMPUS/DOCUMENTS/nature09250.pdf | [f-pulsed-laser-inverted] MIT copy: "determined by means of pulsed laser spectroscopy at wavelengths around 6.01 mm" and "From equation (1), we deduce an r.m.s. proton charge radius of rp = 0.84184(36)(56) fm" (text layer prints = as 5)
- CONFIRMED | 206.2949 ± 0.0032 meV | https://web.mit.edu/OLYMPUS/DOCUMENTS/nature09250.pdf | [f-energy] MIT copy p. 215: "This frequency corresponds to an energy of DE~ 5 206.2949(32) meV" (5 is the mis-encoded =)
- CONFIRMED | The paper also prints 49,881.88(76) GHz. The energy belongs to the hyperfine component they measured, not to the pure Lamb splitting, so the formula below is theirs for that component. | https://web.mit.edu/OLYMPUS/DOCUMENTS/nature09250.pdf | [f-freq-component] MIT copy: "The centroid position of the 2S(F=1)1/2-2P(F=2)3/2 transition is 49,881.88(76) GHz"; eq. (1) is given "for our particular transition"
- CONFIRMED | E(r) = 209.9779 − 5.2262 r² + 0.0347 r³ | https://web.mit.edu/OLYMPUS/DOCUMENTS/nature09250.pdf | [f-equation1] MIT copy eq. (1): 209.9779(49) - 5.2262 rp^2 + 0.0347 rp^3 meV (signs mis-encoded as { and z)
- CONFIRMED | The first number carries a published theory uncertainty of 0.0049 meV. | https://web.mit.edu/OLYMPUS/DOCUMENTS/nature09250.pdf | [f-theory-sigma] MIT copy p. 213: "The uncertainty of 0.0049 meV in DE~ is dominated by the proton polarizability term"
- CONFIRMED | A femtometre is a millionth of a billionth of a metre. | https://physics.nist.gov/cuu/Units/prefixes.html | [f-femto] femto = 10^-15 = 10^-6 x 10^-9
- CONFIRMED | Against the accepted value of the day, 0.8768 ± 0.0069 fm | https://arxiv.org/pdf/0801.0028v1 | [f-codata06-radius] arXiv:0801.0028v1 Table 45, adjustment 4 ("4 is the final adjustment"): Rp/fm 0.8768(69); also in the 2010 abstract
- CONFIRMED | A proton has no hard surface to put a ruler against. Its charge has a spread. That spread nudges the energy levels of any atom built around it, and the nudge leaves a mark in the frequency of the light the atom absorbs. | https://www.nature.com/articles/nature09250 | [f-hero-surface] general physics; the abstract supports the finite-size effect on levels ("affected by as much as 2 per cent")
- CONFIRMED | In 2026 a group at the Max Planck Institute of Quantum Optics in Garching published two measured transitions of ordinary hydrogen, from the 2S state to the two 6P fine-structure levels. | https://www.nature.com/articles/s41586-026-10124-3 | [f-mais-who] affiliations list MPQ Garching for six of seven authors (Pohl at Mainz); transitions 2S-6P1/2 and 2S-6P3/2, eqs (4), (5)
- CONFIRMED | HFS moves the result to the hyperfine centroid: −132,985.25 kHz. | https://www.nature.com/articles/s41586-026-10124-3 | [f-hfs] Results after eq. (8) and Table 1 row "HFS correction ... -132,985.25 0.01"
- CONFIRMED | The components already carry the experiment’s other corrections, which the page does not apply again. | https://www.nature.com/articles/s41586-026-10124-3 | [f-components-corrected] Table 1 is the corrections to the centroid, recoil included; (730,690,111,486.30 + 2 x 730,690,516,650.91)/3 - 132,985.25 = 730,690,248,610.79, the printed eq. (8), so only HFS is left to apply
- CONFIRMED | Published centroid: 730,690,248,610.79 kHz. Published radius: 0.8406 ± 0.0015 fm, printed as 0.0005 fm from QED and 0.0014 fm from the measurement. | https://www.nature.com/articles/s41586-026-10124-3 | [f-published-centroid] eqs (8) and (9): 730,690,248,610.79(48) kHz and 0.8406(5)QED(14)exp fm
- CONFIRMED | The source CSV independently checks the published comparison: | https://www.nature.com/articles/s41586-026-10124-3 | [f-csv-55] "disagrees with the CODATA 2014 proton radius16 by 5.5 sigma"; from the CSV, (0.8751-0.8406)/hypot(0.0061,0.0015) = 5.492
- CONFIRMED | That CSV is a radius inventory, not the measured frequencies used in the inference above. | https://media.springernature.com/original/springer-static/esm/art%3A10.1038%2Fs41586-026-10124-3/MediaObjects/41586_2026_10124_MOESM3_ESM.csv | [f-csv-not-frequencies] MOESM3 header: DOI,Year,Label,Reference,Theory source,Proton radius (fm),Proton radius uncertainty (fm)
- CONFIRMED | Ordinary hydrogen’s 1S-2S transition is measured so precisely that it pins a combination of the Rydberg constant and the proton radius. | https://www.nature.com/articles/s41586-026-10124-3 | [f-1s2s-pins] also "By combining our measurement with the precisely known 1S-2S transition frequency18, we determine rp"
- CONFIRMED | The Rydberg constant sets the scale of every hydrogen line. | https://www.nature.com/articles/s41586-026-10124-3 | [f-rydberg-scale] general physics; the paper converts all terms to SI with R-infinity
- CONFIRMED | Its last discussion paragraph combines the measured hydrogen 1S-2S interval with Lamb shifts calculated from the muonic radius, and prints a new Rydberg constant: R = 10,973,731.568160(16) per m. | https://web.mit.edu/OLYMPUS/DOCUMENTS/nature09250.pdf | [f-2010-rydberg-method] MIT copy p. 216: "we use the precisely measured H(1S-2S) interval4,5, the H(1S)- and H(2S)-Lamb shifts calculated with our rp value ... R = 10,973,731.568160(16) m-1". Locator note: an indented two-sentence outlook paragraph ("Spectroscopy in hydrogenic atoms continues to challenge...") follows it, so it is the last paragraph of discussion, not the last of the text
- CONFIRMED | that is Computing…, printed as 4.9 standard deviations; and the new value is Computing… more precise, printed as 4.6 times. | https://web.mit.edu/OLYMPUS/DOCUMENTS/nature09250.pdf | [f-2010-rydberg-49-46] MIT copy: "This is 2110 kHz/c or 4.9s away from the CODATA value3, but 4.6 times more precise" (2 is the mis-encoded minus); my arithmetic: -110.02 kHz, 4.91 sigma, 73/16 = 4.56
- CONFIRMED | CODATA 2006 had 10,973,731.568527(73) per m. | https://arxiv.org/pdf/0801.0028v1 | [f-codata06-rydberg] arXiv:0801.0028v1 Table 49 and Table 45 adj. 4: 10 973 731.568 527(73) m-1
- CONFIRMED | Garching paper reports a correlation of 0.94 between its two values | https://www.nature.com/articles/s41586-026-10124-3 | [f-mais-rydberg] "Pearson correlation coefficient r = 0.94 with equation (9)"
- CONFIRMED | The 2026 paper tested that too, by comparing its measured centroid with the Standard Model prediction built from the muonic radius 0.84060 ± 0.00039 fm. | https://www.nature.com/articles/s41586-026-10124-3 | [f-sm-test-radius] "we use the muonic value of rp as input to equation (1)"; the muonic measurement15 is "rp = 0.84060(39) fm"; 210.0 x 2 x 0.8406 x 0.00039 = 138 Hz, the Methods share
- CONFIRMED | the paper prints 0.00 ± 0.53 kHz. | https://www.nature.com/articles/s41586-026-10124-3 | [f-sm-diff] "0.00(53) kHz"
- CONFIRMED | That comparison uses the paper’s full 0.23 kHz prediction uncertainty, which includes the muonic radius. | https://www.nature.com/articles/s41586-026-10124-3 | [f-sm-023] eq. (10): (18)QED(14)rp = (23) kHz
- CONFIRMED | Equation (10) prints the muonic radius’s share of the prediction uncertainty as 0.14 kHz. | https://www.nature.com/articles/s41586-026-10124-3 | [f-eq10-014] eq. (10) (14)rp; Methods "contributes 138 Hz"
- CONFIRMED | The same experiment checks the separation of its two transitions against theory, a separation that does not depend on the proton’s size. | https://www.nature.com/articles/s41586-026-10124-3 | [f-separation-independent] "at our level of accuracy does not depend on r p"; Methods put the size terms at 70 mHz. The page states the caveat itself ("does not establish exact radius-independence of every higher-order physical contribution")
- CONFIRMED | The paper prints the separation as 405,164.62 ± 0.97 kHz, the theory as 405,164.51 ± 0.01 kHz and their difference as 0.11 ± 0.97 kHz. | https://www.nature.com/articles/s41586-026-10124-3 | [f-sep-numbers] eq. (6) 405,164.62(97) kHz; QED 405,164.51(1) kHz; difference 0.11(97) kHz
- CONFIRMED | the entire applied experiment-specific correction to the centroid is 1.74 ± 0.48 kHz (Table 1) | https://www.nature.com/articles/s41586-026-10124-3/tables/1 | [f-correction-174] Table 1 (fetched with a browser UA): "Subtotal (experiment-specific contributions) / 1.74 / 0.48"
- CONFIRMED | Original component estimates, with their published total errors: | https://www.nature.com/articles/s41586-026-10124-3 | [f-components] eqs (4), (5): 730,690,111,486.30(69) and 730,690,516,650.91(66) kHz
- CONFIRMED | The separation uncertainty is supplied by the authors. Treating the total component errors as independent would lose their correlations, so the page does not do it. | https://www.nature.com/articles/s41586-026-10124-3 | [f-sep-uncertainty-supplied] printed 0.97 kHz vs hypot(0.69,0.66) = 0.955; Methods give a correlated dc-Stark correction (r = -0.30)
- CONFIRMED | The paper’s illustrated scan releases fitted, corrected frequencies for atoms at different speeds. | https://www.nature.com/articles/s41586-026-10124-3 | [f-scan-released] Fig. 2d caption: fitted resonance frequencies by velocity group, "corrected for light force, QI and second-order Doppler shifts and all other corrections"
- CONFIRMED | Figure 2 source workbook, sheet “d, from fit to exp.” | https://media.springernature.com/original/springer-static/esm/art%3A10.1038%2Fs41586-026-10124-3/MediaObjects/41586_2026_10124_MOESM4_ESM.xlsx | [f-workbook-sheet] MOESM4 (sha256 f20a5b67..., identical to research/.../figure2-source.xlsx) has a sheet named "d, from fit to exp."; the article lists it as Source Data Fig. 2
- CONFIRMED | the article says its analysis code is available from the corresponding author. | https://www.nature.com/articles/s41586-026-10124-3 | [f-code-available] "All code used for the data analysis and simulations of this study is available from the corresponding author."
- CONFIRMED | The condensed electronic experimental record is available on Zenodo under CC BY | https://api.datacite.org/dois/10.5281/zenodo.15874385 | [f-zenodo-ccby] DataCite: "Creative Commons Attribution 4.0 International", IsSupplementTo 10.1038/s41586-026-10124-3; the article's Data availability cites Zenodo ref. 70, zenodo.15874385. zenodo.org returns 403 to curl (positive control: DataCite resolves the same DOI)
- CONFIRMED | The electronic article and its source files are CC BY 4.0; the authors are credited above. | https://www.nature.com/articles/s41586-026-10124-3 | [f-cc-by] "Open Access This article is licensed under a Creative Commons Attribution 4.0 International License"; the source data files are part of the article's ESM and no exception is stated
- CONFIRMED | Pohl and Hänsch also belonged to the original muonic collaboration. | https://api.crossref.org/works/10.1038/nature09250 | [f-pohl-haensch] both in the 2010 list ("Theodor W. Haensch1") and the 2026 list
- CONFIRMED | Randolf Pohl, Aldo Antognini, François Nez, Fernando D. Amaro, François Biraben, João M. R. Cardoso | https://api.crossref.org/works/10.1038/nature09250 | [c-pohl-authors] I compared data.js AUTHORS2010 (32 names) with Crossref's 32, in order: identical
- CONFIRMED | independently report 0.8433 ± 0.0031 fm from different transitions. Both experiments support the small scale. | https://arxiv.org/abs/2604.26401v1 | [f-bullis-radius] arXiv abstract: "r_p = 0.8433(31) fm", from 2S-nS with n = 8, 9, 10; no author shared with the Garching paper
- CONFIRMED | Bullis and colleagues, at Colorado State University | https://arxiv.org/pdf/2604.26401v1 | [f-bullis-csu] arXiv PDF affiliation 1: Colorado State University, Fort Collins
- CONFIRMED | Both experiments support the small scale. | https://arxiv.org/abs/2604.26401v1 | [f-bullis-codata-agree] "These are in good agreement with the CODATA 2022 recommended values"; 0.8433(31) and 0.8406(15) both sit at the small radius
- CONFIRMED | recommends 0.84075 ± 0.00064 fm. It includes muonic measurements, so it is context, not another independent replication. | https://physics.nist.gov/cuu/pdf/JPCRD2022CODATA.pdf | [f-codata-recommends] Table XVI column Complete: 0.840 75(64) fm; the Complete adjustment includes the muonic data
- CONFIRMED | It was published on 16 September 2025, before both electronic experiments used here | https://physics.nist.gov/cuu/pdf/JPCRD2022CODATA.pdf | [f-codata22-published] JPCRD first page: "Published Online: 16 September 2025"
- MINOR | It was published on 16 September 2025, before both electronic experiments used here | https://api.crossref.org/works/10.1103/RevModPhys.97.025002 | [f-codata22-rmp] the excerpt does not support the claim it is filed under: the same adjustment was published in Rev. Mod. Phys. 97, 025002 on 30 April 2025 (Crossref issued 2025-04-30), and the Garching paper cites that version (its ref. 1). "It was published on 16 September 2025" is true only of the JPCRD copy the page links; "before both electronic experiments" holds either way. [declined] fix not cheap: a trial edit tripped the verifier's frozen visible-text fingerprint (record.json, pinned by another layer) and its structural-numeral rule, and was reverted
- CONFIRMED | That recommendation rests mainly on the muonic data. | https://www.nature.com/articles/s41586-026-10124-3 | [f-codata-mainly-muonic] Fig. 1 caption: CODATA 2022 "essentially corresponds to the muonic value owing to the exceptionally low uncertainty of the latter"
- CONFIRMED | the muonic data without electronic atom data give 0.84060 ± 0.00066 fm, and the electronic hydrogen and deuterium frequencies without muonic data give 0.8529 ± 0.0043 fm, 2.8 σ larger by CODATA’s own comparison | https://physics.nist.gov/cuu/pdf/JPCRD2022CODATA.pdf | [f-codata-xvi] Table XVI (my pdftotext reads the columns in order): No muonic 0.8529(43), No electronic 0.840 60(66); "For both rp and rd the H-D only value exceeds the muonic value by 2.8 sigma"; arXiv:2409.03787v1 prints the same 2.8 sigma
- CONFIRMED | Those electronic data end on 31 December 2022, before both electronic experiments used here. | https://arxiv.org/abs/2409.03787 | [f-codata-cutoff] "all theoretical and experimental data available through 31 December 2022"
- CONFIRMED | The adjustment’s overview prints the no-muonic value as 0.8529(13); its own relative uncertainty, 51 × 10⁻⁴, and its 2.8 σ both imply an uncertainty of 0.0043 fm, as the table prints. | https://physics.nist.gov/cuu/pdf/JPCRD2022CODATA.pdf | [f-codata-overview] Sec. I.B: "0.8529(13) [51 x 10-4 ]"; 51e-4 x 0.8529 = 0.00435 and (0.8529-0.8406)/2.8 gives 0.0043 with 0.00066 removed in quadrature
- CONFIRMED | A specialist review preprint, not another measurement. | https://arxiv.org/abs/2604.15546v2 | [f-miller-review] "Prepared for Encyclopedia of Nuclear Physics"; a review chapter, no new measurement
- CONFIRMED | The two share data and theory, so this is a revision, not an independent disagreement. | https://arxiv.org/html/2212.13782v5 | [f-muonic-moved] Pachucki et al. table: muonic-H experiment "Presented by Antognini et al. [6], Pohl et al. [109]..."; r_C 0.840 60(39) "this review" vs 0.840 87(39) "previous work". Same measurements, revised theory from the same line of work, so "revision, not an independent disagreement" holds; "share ... theory" is loose but not false
- CONFIRMED | Electron-scattering analyses still limit any wider claim of universal agreement. | https://www.nature.com/articles/s41586-026-10124-3 | [f-electron-scattering] Fig. 1 caption: scattering not shown "as different analyses give significantly different values of rp"
- CONFIRMED | Earlier corroboration existed; this interval is not a claim that the field had no evidence in between. | https://www.nature.com/articles/s41586-026-10124-3 | [f-earlier-corroboration] 2S-4P (2017) "favoured the muonic result"
- CONFIRMED | The row labelled “1S-3S (2018)” carries the DOI 10.1103/PhysRevLett.120.183003, which resolves to an unrelated article. | https://api.crossref.org/works/10.1103/PhysRevLett.120.183003 | [f-doi-183003] Crossref title "Mapping the Complete Reaction Path of a Complex Photochemical Reaction" (Smith et al.)
- CONFIRMED | The paper that row means is 10.1103/PhysRevLett.120.183001. | https://api.crossref.org/works/10.1103/PhysRevLett.120.183001 | [f-doi-183001] Crossref: Fleurbaey et al., "New Measurement of the 1S-3S Transition Frequency of Hydrogen". Stronger than the record says: the CSV row's Reference 3 is the Garching paper's ref. 3, which is Fleurbaey, PRL 120, 183001
- CONFIRMED | Separate metadata records the article’s actual online publication date, 11 February 2026, and its DOI. | https://www.nature.com/articles/s41586-026-10124-3 | [f-2s6p-published] "Published: 11 February 2026"; control-2026.json carries date 2026-02-11 and the DOI
- CONFIRMED | The electronic values there have been re-evaluated with updated theory, so they are not necessarily the values the original papers printed. | https://www.nature.com/articles/s41586-026-10124-3 | [f-csv-reevaluated] Fig. 1 caption: "The rp values are determined by combining each measurement with the 1S-2S transition frequency18 and equation (1)"; the CSV Theory source column reads CODATA2022
- CONFIRMED | The other famous muon anomaly. There the reference calculation moved; here the reference value, and the Rydberg constant with it, moved. | src/content/strata/the-gap-that-changed-sides.md | [g-sister-gap] sister dek: "how the reference calculation changed"
- CONFIRMED | Move every mass together and relative comparisons stay fixed. The same blind direction appears here in a frequency subtraction. | src/content/strata/the-kilogram-that-could-not-lose-weight.md | [g-sister-kg] sister dek: "Shift every artifact together and every recorded difference stays fixed"
- CONFIRMED | A detector keeps intensity and loses phase. Here, the check keeps the separation and loses a common shift. | src/content/strata/what-the-detector-could-not-record.md | [g-sister-detector] sister dek: records intensity, "The phase is never recorded"
- CONFIRMED | The atom’s spatial scale and its electron cloud. Here, the proton’s charge radius is read from the light that cloud absorbs. | src/content/strata/atom-empty-space.md | [g-sister-atom] sister dek computes the 1s cloud and the atom's scale
- CONFIRMED | A companion in the same wave. | src/content/strata/the-visitor-gravity-could-not-fit.md | [g-sister-visitor] both dated 2026-09-23, the At Full Strength wave (commit d2ef559bfe7)
- CONFIRMED | the Rydberg frequency, which has since fallen by about 110 kHz from its CODATA 2006 value. | public/strata/the-proton-that-stayed-small/data/rydberg.json | [d-dek-110] recreated: engine rows -112.4 (Garching), -108.0 (Bullis), -110.9 (CODATA 2022) kHz; hand arithmetic with c = 299792458 agrees
- CONFIRMED | Planted with the 2010 contrast, its control lands 24.6 of its own standard uncertainties from the old radius, a sensitivity margin that falls to 4.96 σ once the old value’s uncertainty is counted, while its fine-structure check stays blind to the same shift. | research/the-proton-that-stayed-small/verify-the-proton-that-stayed-small.mjs | [d-headline] recreated: powerSeparation 24.6 sigma, baselineSeparation 0.0, powerHistorical 4.958 sigma; mutation: "26.4" in the sentence makes the verifier fail ("visible headline matches checked copy")
- CONFIRMED | This is an inversion of the published transition energy, not a new fit of the resonance counts. | public/strata/the-proton-that-stayed-small/data/claim-2010.json | [d-anchor] recreated: 0.84183113 +- 0.00067073 fm, 5.044 sigma, REPRODUCED within the rounding budget
- CONFIRMED | well inside the spread produced by rounding the printed inputs (the check, below) | research/the-proton-that-stayed-small/verify-the-proton-that-stayed-small.mjs | [d-rounding] recreated: 0.84181219 to 0.84185007 fm, centre inside
- CONFIRMED | Tolerances: 0.000030 fm for the centre, 0.000015 fm for its uncertainty and 0.05 σ for the historical comparison. | public/strata/the-proton-that-stayed-small/data/claim-2010.json | [d-tolerances] claim-2010.json tolerances 3e-05, 1.5e-05, 0.05
- CONFIRMED | The rule, which is this page’s choice: the planted copy must sit at least Computing… standard uncertainties from the old radius, and the old-radius copy must not. | public/strata/the-proton-that-stayed-small/engine.js | [d-rule-threshold] DETECTION_THRESHOLD = 3
- CONFIRMED | So hand this one a world where the old radius is true, and then plant the whole 2010 contrast, 0.8768 → 0.84184 fm, into its own measured frequencies. | public/strata/the-proton-that-stayed-small/engine.js | [d-reset-plant] recreated: reset +13.1 kHz, plant -12.6 kHz, 0.8768 -> 0.8418 fm
- CONFIRMED | The recovered change in squared radius is Computing…, the claimed contrast itself. | public/strata/the-proton-that-stayed-small/engine.js | [d-recovered] recreated -0.0601 fm2; 0.84184^2 - 0.8768^2 = -0.0601
- CONFIRMED | The rule stops confirming beyond Computing… the published value, a measurement uncertainty of Computing…. | public/strata/the-proton-that-stayed-small/engine.js | [d-breakeven] recreated 8.75 times, 4.2 kHz (= 8.75 x 0.48)
- CONFIRMED | It also sweeps Computing… shared shifts and Computing… separation shifts. | public/strata/the-proton-that-stayed-small/engine.js | [d-sweep] recreated 61 shared, 41 separation, leaks 0.0e+0 and 3.2e-10 kHz, 3 refusals
- CONFIRMED | This matrix is the algebra of the two observables, one third and two thirds of the components for the centroid and their difference for the separation. | https://www.nature.com/articles/s41586-026-10124-3 | [d-matrix-algebra] eq. (7) weights 1/3, 2/3; eq. (6) difference; engine matrix [0.333333, 0.666667], [-1, +1]
- CONFIRMED | B = [−1/8 − (8/27)(−7/8)] K = (29/216) K | public/strata/the-proton-that-stayed-small/engine.js | [d-B-formula] my derivation: -1/8 + (8/27)(7/8) = 29/216; K = 1563.9 kHz/fm2 by hand; B = 210.0 reproduces the printed 0.14 kHz rp share, -195.5 gives 0.128
- CONFIRMED | For the leading finite-size contribution, an S level shifts by K r²/n³. | https://www.nature.com/articles/s41586-026-10124-3 | [f-n3-scaling] "the nuclear size correction scales as 1/ n 3"
- CONFIRMED | The engine computes K = Computing… from the | https://physics.nist.gov/cuu/pdf/JPCRD2022CODATA.pdf | [f-K-codata] resolves the record's open question: page 14 laid out with pdftotext -layout puts "(50)" beside E(4)nucl = (2/3) me c2 (Z alpha)4/n3 (mr/me)3 (rN/lambdaC)2, the leading term; (51) is the alpha5 term. Constants alpha 7.297 352 5643(11)e-3, me 9.109 383 7139(28)e-31 kg, mp/me 1836.152 673 426(32) match constants-2022.json
- CONFIRMED | The whole puzzle fits in the check’s blind spot. | public/strata/the-proton-that-stayed-small/engine.js | [d-restore] recreated +13.1 kHz, 0.8768 fm, +0.00 kHz, 0.10 sigma, 7.5 and 27 times
- CONFIRMED | Weighted least squares, with inverse-variance weights. | public/strata/the-proton-that-stayed-small/engine.js | [d-scan] fitScan is inverse-variance WLS; recreated intercept -3.237 +- 21.731 kHz, equal to the workbook's own sheet "d, extrapolation" (-3236.78 Hz, 21730.63 Hz)
- CONFIRMED | The selected control arrived Computing… calendar years after the original claim. | public/strata/the-proton-that-stayed-small/data/control-2026.json | [d-years] 2026 - 2010 = 16
- CONFIRMED | In the source inventory, Computing… hydrogen rows sit more than two standard deviations from the muonic value, treating the uncertainties as independent: | public/strata/the-proton-that-stayed-small/data/comparison.csv | [d-discrepant-rows] recreated 2 of 7: 2S-8D (2022) 3.51 sigma, 1S-3S (2018) 2.80 sigma; next is 1S-3S (2020) at 1.99
- CONFIRMED | The row labelled “1S-3S (2018)” carries the DOI 10.1103/PhysRevLett.120.183003 | public/strata/the-proton-that-stayed-small/data/comparison.csv | [d-csv-1s3s] comparison.csv row 8, byte-identical to MOESM3
- CONFIRMED | The row labelled “2S-6P (2026)” has a year field of 2025 and a blank DOI. | public/strata/the-proton-that-stayed-small/data/comparison.csv | [d-csv-2s6p] row ",2025,2S-6P (2026),-1,..."; comparison.csv sha256 fb66207047dc... equals MOESM3 fetched 2026-10-19
- CONFIRMED | The verdict rests on the two most precise hydrogen determinations on this page, which agree with the small radius. | public/strata/the-proton-that-stayed-small/data/comparison.csv | [d-two-most-precise] 0.0015 (2S-6P), 0.0031 (Bullis); best other CSV hydrogen row 0.0037
- CONFIRMED | The muonic number itself moved. | public/strata/the-proton-that-stayed-small/data/comparison.csv | [d-muonic-row] recreated 0.84060 +- 0.00039 fm (Pachucki et al. 2024 "this review" 0.840 60(39)), -0.00124 fm, 1.9 times 0.00067
- CONFIRMED | Two hydrogen experiments in two laboratories put the Rydberg frequency Computing… below CODATA 2006, each within Computing… of the value the 2010 paper printed | public/strata/the-proton-that-stayed-small/data/rydberg.json | [d-rydberg-since] recreated 108.0 to 112.4 kHz; distances to the 2010 value 2.4 and 2.0 kHz
- CONFIRMED | Each of the two hydrogen values sits within Computing… of what the same leading-order relation predicts for its own radius. | public/strata/the-proton-that-stayed-small/engine.js | [d-rydberg-relation] recreated residuals +1.1, -2.8 (CODATA 2022 +2.1) kHz, max 2.8
- CONFIRMED | As of 2026-09-22 | public/strata/the-proton-that-stayed-small/data/context.json | [d-context] "as_of": "2026-09-22"
- CONFIRMED | frozen input files passed SHA-256 checks. The inversions, edited-record tests, scan fit, sweeps and Rydberg bookkeeping ran in this browser. No upstream service is used. | public/strata/the-proton-that-stayed-small/data.js | [d-sha] recreated: sha256 of the 7 live data files equals record.json 7 of 7; page scripts fetch only ./record.json and ./data/
- CONFIRMED | This layer's check imports and runs the very module this page runs. | research/the-proton-that-stayed-small/verify-the-proton-that-stayed-small.mjs | [d-placard] the verifier imports ../../public/strata/.../engine.js; run from a scratch copy of e7c21dfcc4 with the related strata: 531 assertions, only the browser step (no browser) and its ledger line fail
- MINOR | "dateModified":"2026-09-23" | git show e7c21dfcc4:public/strata/the-proton-that-stayed-small/index.html | [o-datemodified] the page's one JSON-LD block says "dateModified":"2026-09-23", but commit 6294b2c42ad (2026-09-26) added the CODATA paragraph ending "Added 2026-09-26." and commits of 2026-09-27 changed the placard; the machine-readable date understates the last change. [fixed] 2026-10-18: dateModified set to 2026-10-18, and the verifier's assertion that dateModified equals the publication date replaced by one that it is an ISO date not before datePublished
- OBSERVED | Added 2026-09-26. | git show 6294b2c42ad -- public/strata/the-proton-that-stayed-small/index.html; memory/log.d/2026-09-26T1400Z-the-sweep-that-looked.md | [o-added-0926] commit of 2026-09-26 11:39 UTC adds the paragraph; the log describes "the proton layer scopes CODATA 2022 and shows the overview's 0.8529(13)"
- OBSERVED | we searched the Artificial Wasteland built index, the Nature source-data records and web searches for proton-radius interactive fine-structure and power-injection tools on 2026-09-22 and did not find an interactive reconstruction that places the 2010 radius contrast in the blind direction of the 2026 fine-structure check while also showing the radius-sensitive centroid. | research/the-proton-that-stayed-small/README.md | [o-novelty] "Bounded novelty search" records the 2026-09-22 index and web queries; the "Nature source-data records" part is not described there (positive control: the same file read finds "built index"): not kept, a fact about the evidence
- OBSERVED | did not find an interactive reconstruction that places the 2010 radius contrast in the blind direction of the 2026 fine-structure check while also showing the radius-sensitive centroid. | research/the-proton-that-stayed-small/README.md | [f-novelty-recheck] the same dated observation; the record's own later search is later data and cannot test it
- CONFIRMED | Independent observable, overlapping authors | https://www.nature.com/articles/s41586-026-10124-3 | [f-hydrogen-two-labs] Pohl at Johannes Gutenberg-Universitaet Mainz in 2026, at MPQ in 2010; Pohl and Haensch on both papers
- CONFIRMED | (added) The Rydberg table row "Hydrogen 1S-2S with 2S-nS, 2026": cR = 3,289,841,960,252.9(9.7) kHz, an ordinary-hydrogen value ("The two 2026 values use ordinary hydrogen only.") | https://arxiv.org/abs/2604.26401v1 | "Combining the results from this work and the 1S1/2-2S1/2 transition frequency, we extract ... a Rydberg frequency of cR = 3,289,841,960,252.9(9.7) kHz"; rydberg.json matches
- CONFIRMED | (added) The historical comparator "CODATA 2014, later comparison", rendered as 0.8751 +- 0.0061 fm from the CSV | https://arxiv.org/pdf/1507.07956v1 | CODATA 2014 recommended values: "rp 0.8751(61) x 10-15 m"; the CSV row is byte-identical to the paper's Source Data
- CONFIRMED | (added) The single-scan extract (16 velocity groups: mean speed, corrected resonance frequency, uncertainty) from sheet "d, from fit to exp." | https://media.springernature.com/original/springer-static/esm/art%3A10.1038%2Fs41586-026-10124-3/MediaObjects/41586_2026_10124_MOESM4_ESM.xlsx | parsed the sheet with python zipfile: all 16 rows equal single-scan.json exactly; published_extrapolation equals sheet "d, extrapolation" row 0
- CONFIRMED | (added) CODATA 2022 R-infinity in the Rydberg table: R = 10,973,731.568157(12) per m, with radius 0.84075 +- 0.00064 fm, includes muonic data | https://physics.nist.gov/cuu/pdf/JPCRD2022CODATA.pdf | Table XVI column Complete: "10 973 731.568 157(12)" and "0.840 75(64)"
- CONFIRMED | (added) The constants behind K (constants-2022.json): alpha 0.0072973525643, electron mass 9.1093837139e-31 kg, proton-electron mass ratio 1836.152673426 | https://physics.nist.gov/cuu/pdf/JPCRD2022CODATA.pdf | recommended values: 7.297 352 5643(11) x 10-3, 9.109 383 7139(28) x 10-31 kg, 1836.152 673 426(32)
- CONFIRMED | (added) NOTICE.txt: the 2010 paper prints copyright 2010 Macmillan Publishers Limited; the CODATA PDF prints the U.S. Secretary of Commerce; the Zenodo dataset is CC BY 4.0, issued 11 February 2026 | https://web.mit.edu/OLYMPUS/DOCUMENTS/nature09250.pdf | MIT copy p. 213 "(c)2010 Macmillan Publishers Limited. All rights"; NIST PDF footer "U.S. Secretary of Commerce"; DataCite dates Issued 2026-02-11, rights cc-by-4.0

## Findings
- [fixed] MINOR o-datemodified: the JSON-LD said "dateModified":"2026-09-23" though the page was changed on 2026-09-26 (the CODATA paragraph ending "Added 2026-09-26.") and later; it now says "dateModified":"2026-10-18". The verifier's JSON-LD check asserted dateModified === META.date (the publication date), which forbade any later modification; it now asserts an ISO date not before datePublished, and goes red on a dateModified of 2026-09-01.
- [declined] MINOR f-codata22-rmp: "It was published on 16 September 2025, before both electronic experiments used here". Crossref dates the same adjustment in Rev. Mod. Phys. 97, 025002 to 30 April 2025; 16 September 2025 is the J. Phys. Chem. Ref. Data copy the sentence links, and "before both" holds either way. A slip of precision, not false of the linked copy. The cheap edit was tried and reverted: the verifier fingerprints the page's static visible text against record.json ("unbound visible text has not drifted"), which it notes is pinned by another layer, and refuses the new numeral "30"; a fix wants the date carried as a bound fact in context.json and record.json, not a few words.
- [declined] f-2010-rydberg-method: "Its last discussion paragraph" / "final discussion paragraph". An indented two-sentence outlook paragraph follows the R-infinity paragraph in the 2010 letter, but it holds no discussion of results, so the locator is fair (checker's own note).
- [declined] c-codata22-datajs and c-codata06-datajs: the sources tool's DOI MISMATCH ("gives Mohr the initial J.") is a parsing artifact; Crossref's names are Peter J. Mohr, David B. Newell, Barry N. Taylor, character for character as the page has them (checker's own note).
- [declined] f-zenodo-ccby and the Bullis link: zenodo.org/records/15874385 and journals.aps.org return 403 to curl; DataCite and Crossref resolve both DOIs, so these are bot blocks, not dead links (checker's own note).