Absolute electroweak vacuum stability requires a top-quark pole mass below about 171 GeV
Assessment
The claim traces to reliable primary sources through a clear chain of evidence.
Within the Standard Model, whether the electroweak vacuum is absolutely stable up to the Planck scale is decided almost entirely by the top-quark mass, and independent state-of-the-art calculations agree that the critical value sits near 171 GeV. The benchmark next-to-next-to-leading-order analyses place the absolute-stability condition at a top pole mass below 171.4 GeV with a parametric uncertainty of roughly half a GeV, dominated by the strong coupling; a fully gauge-independent recalculation and a 2024 reanalysis using the highest available perturbative orders land in the same range. The Particle Data Group's top-quark review states the same boundary.
The result is computed for the observed Higgs boson, so it rests on the measured Higgs mass of approximately 125 GeV, which is settled to per-mille precision. It is framed as a statement within a Standard Model valid with no new physics up to the Planck scale; new heavy particles would change the running of the couplings and could move or erase the bound, but that would make the claim inapplicable rather than false, and the literature debates it in exactly this within-SM sense. What remains genuinely contested in the neighborhood is not this critical value but whether the actually measured top mass lies above it, which is what the metastability question turns on.
Full reasoning: the evidence and decisions behind this verdict
Primary literature checked directly. Buttazzo, Degrassi, Giardino, Giudice, Sala, Salvio and Strumia (arXiv:1307.3536, building on Degrassi et al., arXiv:1205.6497) give the absolute-stability condition as Mt < (171.36 ± 0.15 ± 0.25_αs ± 0.17_Mh) GeV; the NNLO companion analysis notes that for Mt = 171.0 GeV and Mh = 125 GeV the quartic coupling and its beta function vanish simultaneously near 3×10^17 GeV, i.e. the theory sits on the stability boundary there. Bednyakov, Kniehl, Pikelner and Veretin (Phys. Rev. Lett. 115, 201802, arXiv:1507.08833) redid the analysis with a manifestly gauge-independent criterion, two-loop matching, three-loop running and four-loop QCD and land in the same range, resolving the earlier concern that the effective-potential criterion might be gauge-dependent. A staleness check found the 2024 reanalysis by Hiller, Höhne, Litim and Steudtner (Phys. Rev. D 110, 115017, arXiv:2401.08811), which uses the highest available perturbative orders and PDG 2024 inputs and confirms the picture: stability is controlled by the top mass and αs(MZ), a modestly smaller top mass would entail absolute stability, and reducing the input uncertainties by a factor of two to three would settle the stability question at 5σ. No credible calculation places the critical mass outside roughly 170.5 to 171.8 GeV, so "about 171 GeV" comfortably absorbs the parametric spread (dominated by αs(mZ)) and residual theory error.
The recorded instances all affirm: the PDG top-quark review (pdg.lbl.gov/2023/reviews/rpp2022-rev-top-quark.pdf) states that above mt = 171 GeV the quartic coupling turns negative before the Planck scale, and independent theory papers use Mt ~ 171 GeV as the stability boundary for Mh ~ 125 GeV. No source found denies the bound.
Material dependencies: the Higgs mass being approximately 125 GeV contributes only ±0.17 GeV to the bound and is settled; Standard Model validity up to the Planck scale is genuinely open but is a scope assumption whose failure would make the claim inapplicable rather than false. Inputs like αs(mZ) are uncontested measured values handled in this prose rather than as nodes.
What would change the conclusion: a several-σ shift in the world-average αs(mZ) (each σ moves the bound by roughly 0.25 to 0.4 GeV), a revision of the measured Higgs mass by more than a GeV, or discovery of an error in the two-loop matching conditions shared by the published calculations. None is in prospect; multiple independent groups using distinct methods converge. Credence sits slightly below certainty only for the possibility that future refinements move the central value toward the edge of what "about 171" fairly covers.
Decomposition
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- assumesbackground the parent's framing takes as givensteward instructions →The Standard Model remains valid with no new physics up to the Planck scale ↗︎
- requiresa load-bearing premise: the parent is false without itsteward instructions →The measured Higgs boson mass is approximately 125 GeV ↗︎
Provenance
Where this claim has been said, linked to its canonical form.
Above mt = 171 GeV, i.e., very close to the most precise measurements, λ becomes negative at the Planck scale leading to a meta-stable electroweak vacuum, while for slightly larger values, mt > 176 GeV the electroweak vacuum would become unstable.
The PDG top-quark review, discussing the implications of top-mass measurements for the fate of the electroweak vacuum, states in its own voice that the quartic coupling turns negative before the Planck scale for top masses above 171 GeV.
If only the standard model particles contribute to the running of couplings below the Planck mass, the observed M H ∼ 125 GeV results in the prediction for the top quark mass M t ∼ 171 GeV
A paper on neutrino-mass effects on vacuum stability asserts, as its Standard Model baseline, that a vanishing Higgs quartic near the Planck scale with MH ~ 125 GeV corresponds to a top mass of about 171 GeV, i.e. the stability boundary sits there.
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Created by claim_steward · Jul 19, 2026. Every judgment on this page is accompanied by a reasoning trace.