Claim

The study reported a 4-ppm measurement of antihydrogen’s ground-state hyperfine splitting, improving the prior state-of-the-art precision by two orders of magnitude.

Type QUANTITATIVE · truth-evaluable: yes · status at snapshot: ACTIVE · created seq 21914

Referenced 122 times: checked 2, looked up by assistants 0, viewed 71, shared 49. A count of attention, not evidence.

Topics

Physics · 1efd24fe

Assessment

Supported

Score: 0.9121 under ledger-default@0.3.0 at snapshot 27745

2 of 4 review checks done · 1 counted · 1 by the author only

2 independent evidence lineages · review checks 1 of 4 · stability MEDIUM

Main unresolved issue: 4 counted evidence items have no independence review; repeats of one origin may be counted as several coverage:bdd6be06-a995-8c6c-abf9-d2d7066db54a

Not yet independently audited.Evidence reviewed so far supports this claim, but only 1 of 4 review checks has been done.A quoted passage from nature.com was not found on the page when Galedra fetched it.

Why?

Strongest counted support: The primary study directly reports 4-ppm precision and a two-order-of-magnitude improvement. weight 1.800000 evidence

Suppressed as dependent: The quoted passage directly reports a 4-ppm antihydrogen ground-state hyperfine measurement and two-order-of-magnitude precision improvement.

Review gaps: qualifiers reviewed, opposing search done, independence reviewed

What would most change this: One independent, direct measurement that contradicts this claim would move it from Supported to Unresolved.

Hide calculation

0.9121 under ledger-default@0.3.0 at snapshot 27745 · state Supported · Review checks: 1 of 4 · stability MEDIUM · 4 sources, 2 independent lineages

Model ledger-default@0.3.0 (the default model, not the answer) · snapshot 27745 · trace sha256:650d2ba91b46867950ab0a83f15349a1202d7a3fd421b488daac6dc4294785d0

Last changed at entry seq 25633; nothing logged since has borne on this claim.

How the number was reached

Each counted link is weighed by multiplying the factors the model declares; a factor it does not declare is not shown. Every factor name below links to what that number means.

Link	Working	Weight	Counted as
0a063d1d support	relevance DIRECT 2.0 × observation DIRECT_TEXT 0.9 × interpretation 0 steps, 1 − 0.15 × 0 1.000000 × authenticity UNVERIFIED 1.0 × extraction UNVERIFIED 1.0 × provenance INDEPENDENT 1.0 × edition NAMED_OR_UNRELATED 1	1.800000	1.800000
4bb018b8 support	relevance DIRECT 2.0 × observation DIRECT_TEXT 0.9 × interpretation 0 steps, 1 − 0.15 × 0 1.000000 × authenticity UNVERIFIED 1.0 × extraction UNVERIFIED 1.0 × provenance INDEPENDENT 1.0 × edition NAMED_OR_UNRELATED 1	1.800000	0.000000 (dependent strongest only, kept 0a063d1d)
30c9648a support	relevance MODERATE 0.6 × observation DIRECT_TEXT 0.9 × interpretation 0 steps, 1 − 0.15 × 0 1.000000 × authenticity UNVERIFIED 1.0 × extraction UNVERIFIED 1.0 × provenance INDEPENDENT 1.0 × edition NAMED_OR_UNRELATED 1	0.540000	0.540000
cba033a0 qualify	relevance DIRECT 2.0 × observation MEASUREMENT 1.0 × interpretation 0 steps, 1 − 0.15 × 0 1.000000 × authenticity UNVERIFIED 1.0 × extraction UNVERIFIED 1.0 × provenance INDEPENDENT 1.0 × edition NAMED_OR_UNRELATED 1	2.000000	0.000000 (non directional)

prior 0.50 → log-odds 0.000000 + 2.340000 (the counted weights) = 2.340000 → probability 0.9121

Under neighbouring settings of the same model: 0.8373 to 0.9544, a spread of 0.1171.

Half-even rounding, six places for weights and four for the probability. The same inputs under the same model reproduce this exactly; that is what the trace hash above is for. How a score is worked out explains every factor, why it is there, and what the model sets it to.

Your view

Registered views

Nobody has registered a view yet.

Registered views are personal belief, not evidence: they never change Galedra's assessment. Affiliations are self-declared and shown only for groups of 5 or more.

Checked as part of

Statements this claim was broken out of. The claim is scored on its own; a statement's reading only counts its claims.

“The study reported a 4-ppm measurement of antihydrogen’s ground-state hyperfine splitting, improving the prior state-of-the-art precision by two orders of...” · 1 claim · 29 September 2026
“A 2026 Nature experiment measured the antihydrogen ground-state hyperfine splitting with 4-ppm precision.” · 3 claims · 29 September 2026

Evidence for

The primary study directly reports 4-ppm precision and a two-order-of-magnitude improvement.

From Four ppm measurement of the antihydrogen ground-state hyperfine splitting Read 2026-09-29 Relevance DIRECT Steps 0 Counted

Exact abstract result.
The primary article describes the experiment’s reproducibility uncertainty as part of its precision analysis.

From Four ppm measurement of the antihydrogen ground-state hyperfine splitting Read 2026-09-29 Relevance MODERATE Steps 0 Counted

Additional primary-method context for the precision claim.
The quoted passage directly reports a 4-ppm antihydrogen ground-state hyperfine measurement and two-order-of-magnitude precision improvement.

From Four ppm measurement of the antihydrogen ground-state hyperfine splitting Read 2026-09-29 Relevance DIRECT Steps 0 Counted

The excerpt states both quantitative results.

Evidence against

None.

Qualifications

The 4-ppm result is a 1-T, microwave measurement of a1S/h from roughly 24,000 anti-atoms with separate statistical and systematic uncertainties.

From Four ppm measurement of the antihydrogen ground-state hyperfine splitting Read 2026-09-29 Relevance DIRECT Steps 0 Counted

Adds measured quantity, sample size, field condition, uncertainty components, prior baseline, and antiproton-structure sensitivity.

Suppressed as dependent

Evidence	Group	Kept instead
c9419f2d		0a063d1d

Inferences

Concluded from

None.

Used as a premise in

None.

An inference is interpretation, not evidence: it never changes the assessment of its conclusion. Each premise is a claim with its own evidence.

Threads

None. Threads are for disagreements about how a determination was made — a statement whose figures are not in the passage it rests on, two sources that may share an origin. Something about the world belongs in the evidence above.

Claim edges

None. Edges are stored and displayed; v0.1 does not propagate probability across them.

Review checklist

Review checks: 1 of 4

2 checks by this claim's own author, alongside the independent review above. 1 QUALIFIER CHECK · 1 EVIDENCE VERIFICATION. A check by the person who recorded a claim does not raise its review coverage.

Check	Done	By
qualifiers reviewed	no
opposing search done	no
independence reviewed	no
primary source reviewed	yes	0a063d1d, 4bb018b8, 30c9648a, cba033a0

Summary

Supported. The main support is: The primary study directly reports 4-ppm precision and a two-order-of-magnitude improvement. 1e127bbe

1 further item repeats the same origin and is not independent evidence. c9419f2d

Qualifier: The 4-ppm result is a 1-T, microwave measurement of a1S/h from roughly 24,000 anti-atoms with separate statistical and systematic uncertainties. 87a2ef88

Review checks: 1 of 4. coverage:bdd6be06-a995-8c6c-abf9-d2d7066db54a

Generated by stub-v0.1; every sentence cites graph ids.

Contribution history

seq	event	detail
21914	APPENDED
21915	ACCEPT	AUTOMATIC_AFTER_VALIDATION
21932	LINK_EVIDENCE	by 1efd24fe (accepted)
22002	LINK_EVIDENCE	by 1efd24fe (accepted)
24571	TASK_RESULT	by 1efd24fe (accepted)
25632	TASK_RESULT	by 1efd24fe (accepted)

Score trace

{
  "claim": "bdd6be06-a995-8c6c-abf9-d2d7066db54a",
  "links": [
    {
      "link": "197d3b68-980d-8d88-9799-91dc0a063d1d",
      "group": null,
      "edition": "NAMED_OR_UNRELATED",
      "evidence": "28080f36-df20-8bfd-b252-7cf71e127bbe",
      "direction": "SUPPORT",
      "magnitude": "1.800000",
      "relevance": "DIRECT",
      "extraction": "UNVERIFIED",
      "provenance": "INDEPENDENT",
      "observation": "DIRECT_TEXT",
      "source_type": "PRIMARY_TEXT",
      "authenticity": "UNVERIFIED",
      "audit_confirmed": false,
      "effective_weight": "1.800000",
      "interpretive_steps": 0
    },
    {
      "kept": "197d3b68-980d-8d88-9799-91dc0a063d1d",
      "link": "392a7c9d-4e94-8c7f-a529-ddeb4bb018b8",
      "group": null,
      "reason": "dependent_strongest_only",
      "edition": "NAMED_OR_UNRELATED",
      "evidence": "c0f71b6c-486c-8731-8896-1619c9419f2d",
      "direction": "SUPPORT",
      "magnitude": "1.800000",
      "relevance": "DIRECT",
      "extraction": "UNVERIFIED",
      "provenance": "INDEPENDENT",
      "observation": "DIRECT_TEXT",
      "source_type": "PRIMARY_TEXT",
      "authenticity": "UNVERIFIED",
      "audit_confirmed": false,
      "effective_weight": "0.000000",
      "interpretive_steps": 0
    },
    {
      "link": "6b480bc7-3069-858e-aacb-a8b230c9648a",
      "group": null,
      "edition": "NAMED_OR_UNRELATED",
      "evidence": "82e2218d-f061-801c-9808-851c7af3581a",
      "direction": "SUPPORT",
      "magnitude": "0.540000",
      "relevance": "MODERATE",
      "extraction": "UNVERIFIED",
      "provenance": "INDEPENDENT",
      "observation": "DIRECT_TEXT",
      "source_type": "PRIMARY_TEXT",
      "authenticity": "UNVERIFIED",
      "audit_confirmed": false,
      "effective_weight": "0.540000",
      "interpretive_steps": 0
    },
    {
      "link": "a798315d-3099-8ecf-bd03-4293cba033a0",
      "group": null,
      "reason": "non_directional",
      "edition": "NAMED_OR_UNRELATED",
      "evidence": "c3bba571-3ab8-8366-8cf2-41cc87a2ef88",
      "direction": "QUALIFY",
      "magnitude": "2.000000",
      "relevance": "DIRECT",
      "extraction": "UNVERIFIED",
      "provenance": "INDEPENDENT",
      "observation": "MEASUREMENT",
      "source_type": "PRIMARY_TEXT",
      "authenticity": "UNVERIFIED",
      "audit_confirmed": false,
      "effective_weight": "0.000000",
      "interpretive_steps": 0
    }
  ],
  "model": "ledger-default@0.3.0",
  "prior": "0.50",
  "variants": {
    "spread": "0.1171",
    "permissive": "0.9544",
    "conservative": "0.8373"
  },
  "code_hash": "sha256:c61a6fdf35a754a0d7e958df149036a083c0eaeb7d2d2e52704ec32b0c36def7",
  "contested": false,
  "stability": "MEDIUM",
  "claim_type": "QUANTITATIVE",
  "config_hash": "sha256:86768038080b8ab5233f1e4b7aba10af05b5bb44caa432095150b90e81209809",
  "probability": "0.9121",
  "provisional": true,
  "evidence_sum": "2.340000",
  "snapshot_seq": 25633,
  "prior_log_odds": "0.000000",
  "support_groups": 2,
  "model_dependent": false,
  "review_coverage": "0.25",
  "truth_evaluable": true,
  "assessment_state": "SUPPORTED",
  "review_checklist": {
    "qualifiers_reviewed": {
      "by": [],
      "ok": false
    },
    "opposing_search_done": {
      "by": [],
      "ok": false
    },
    "independence_reviewed": {
      "by": [],
      "ok": false
    },
    "primary_source_reviewed": {
      "by": [
        "197d3b68-980d-8d88-9799-91dc0a063d1d",
        "392a7c9d-4e94-8c7f-a529-ddeb4bb018b8",
        "6b480bc7-3069-858e-aacb-a8b230c9648a",
        "a798315d-3099-8ecf-bd03-4293cba033a0"
      ],
      "ok": true
    }
  },
  "contradict_groups": 0,
  "rounding_boundary": false,
  "posterior_log_odds": "2.340000",
  "not_applicable_reason": null,
  "independence_unreviewed": 4
}