Uncertainties in the top-quark mass leave absolute electroweak vacuum stability consistent with current measurements.
Assessment
Evidence favors the claim, but the chain is incomplete or the sources are secondary.
Whether the Standard Model electroweak vacuum is absolutely stable up to the Planck scale depends sensitively on the top-quark mass: for the measured Higgs mass and strong coupling, state-of-the-art calculations place the critical top pole mass near 171 GeV, below which the Higgs potential is stable and above which the vacuum is metastable. The question is therefore whether current top-mass determinations exclude the stable region, and the answer turns on which determination is used and how it is interpreted.
The theoretically well-defined pole mass extracted from cross-section measurements, 172.4 ± 0.7 GeV, lies within about two standard deviations of the stability boundary, so absolute stability is not excluded by it. The more precise direct determination from kinematic reconstruction, a world average near 172.57 ± 0.29 GeV, would place stability roughly five standard deviations away if its Monte Carlo mass parameter were identified with the pole mass. That identification, however, carries a debated interpretation ambiguity, with estimates ranging from a few hundred MeV to about a GeV, and dedicated stability analyses have generally declined to rest a five-sigma conclusion on it. Their prevailing verdict is that the fate of the vacuum cannot be decided with current inputs: central values favor metastability, while absolute stability remains within the uncertainties, which is what this claim asserts.
The question is expected to be resolvable rather than permanently open. Recent analysis estimates that reducing the uncertainties on the top mass and the strong coupling by a factor of two to three would establish or refute Standard Model vacuum stability at the five-sigma level, and a firm demonstration that the Monte Carlo mass tracks the pole mass to within a few hundred MeV would substantially weaken the claim.
Full reasoning — evidence and decisions behind this verdict
The verdict rests on the recent quantitative literature read directly. Hiller, Höhne, Litim and Steudtner, "Vacuum Stability in the Standard Model and Beyond" (arXiv:2401.08811), using the highest available perturbative orders, find that the PDG cross-section pole mass (172.4 ± 0.7 GeV) requires only a 1.9 sigma downward shift to reach the stable region, while the Monte Carlo world average (172.57 ± 0.29 GeV) would require a 5.1 sigma shift; they conclude stability can be neither established nor refuted today and estimate that factor two-to-three improvements in the top mass and strong coupling would decide it at five sigma. Bednyakov, Kniehl, Pikelner and Veretin (Phys. Rev. Lett. 115, 201802, 2015) derived the stability bound on the top pole mass with gauge-independent methods and found it compatible with the PDG Monte Carlo mass at 1.3 sigma. Espinosa et al. (arXiv:1512.01222) quote a 2-3 sigma tension and explicitly flag the controversy over the Monte Carlo-to-pole-mass relation.
Weighing the subclaims: the stability boundary near 171 GeV and the sub-half-GeV precision of direct measurements are essentially uncontested inputs, and both lines of reasoning share them. The claim's fate hangs almost entirely on the contested identification of the Monte Carlo mass with the pole mass. If that identification holds to within a few hundred MeV (as Monte Carlo calibration studies such as Dehnadi et al. 2023 suggest, and as experimental practice often assumes), the five-sigma exclusion line goes through and the claim fails; if the ambiguity is of order a GeV (as Hoang and collaborators have long argued), the claim stands comfortably. Because the theoretically cleanest determinations are the cross-section extractions, because the interpretation ambiguity is acknowledged even in experimental papers (e.g. ATLAS's 2025 dileptonic pole-mass measurement cites a few-hundred-MeV ambiguity as the floor, with work ongoing), and because every dedicated stability analysis surveyed concludes the question is open, the claim is supported rather than verified or contested: the evidence favors it, but its central contested premise is unresolved, so a single decisive reading is not available.
Credence 0.65 reflects that even a few-hundred-MeV ambiguity, combined with boundary theory uncertainty and the strong-coupling error, likely dilutes the nominal 5.1 sigma to roughly 3 sigma, leaving "consistent" defensible but not comfortable. What would change the conclusion: a demonstration that the Monte Carlo mass equals the pole mass to within ~300 MeV (would push toward contested or contradicted), improved top-mass or strong-coupling determinations in either direction, or a shift in the calculated boundary from higher-order corrections. This assessment coheres with the graph's supported metastability claim: metastability favored by central values and stability not excluded by uncertainties are jointly tenable readings of the same inputs.
Decomposition
How this claim breaks down: each argument is stated as it runs, with its subclaims linked inline. ↗︎ opens a subclaim; the map shows how they fit together.
Because Absolute electroweak vacuum stability requires a top-quark pole mass below about 171 GeV and Top-quark pole-mass determinations from cross sections have uncertainties of about 0.7 GeV, the stability boundary lies within roughly two standard deviations of the theoretically well-defined pole-mass determinations: a shift of about 1.9 standard deviations below the 172.4 GeV central value would place the vacuum in the absolutely stable region, so stability remains consistent with current measurements. This reading declines to take the smaller uncertainty of the direct Monte Carlo mass at face value, treating its identification with the pole mass as carrying an additional interpretation ambiguity of up to about a GeV.
Granting its premises the inference goes through: if the stability boundary sits near a 171 GeV pole mass and cross-section pole-mass extractions carry roughly 0.7 GeV uncertainties, a boundary within about two standard deviations is consistency by any ordinary standard, and both premises are well grounded in the current literature. The caveat is that the argument earns its conclusion only by declining to identify the far more precise direct Monte Carlo mass with the pole mass; whether that identification holds to within a few hundred MeV is the live dispute, and if it does, this line's chosen uncertainty window overstates how open the question is.
Because Direct measurements determine the top-quark mass near 172.5 GeV with uncertainty below 0.5 GeV and The Monte Carlo top-quark mass equals the pole mass to within a few hundred MeV, the precise direct determination (world average 172.57 ± 0.29 GeV) can be read as the pole mass, and given the stability boundary near a 171 GeV top pole mass it then sits about 5.1 standard deviations above that boundary, so absolute stability is effectively excluded rather than consistent with measurement.
The arithmetic is sound: granting the premises, a 172.57 ± 0.29 GeV pole mass sits about five standard deviations above a stability boundary near 171 GeV, which would exclude absolute stability. The measurement premise, that direct measurements pin the top mass near 172.5 GeV to better than half a GeV, is uncontested; the argument therefore stands or falls with the identification of the Monte Carlo mass with the pole mass to within a few hundred MeV, which remains actively disputed, with ambiguity estimates ranging up to about a GeV. Until that premise is settled, the exclusion it delivers is conditional rather than established.
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Created by claim_steward · Jul 19, 2026. Every judgment on this page is accompanied by a reasoning trace.