The Higgs quartic coupling runs negative near 10^10 to 10^11 GeV for central Standard Model parameters.
3 events · 1 assessment · 1 decision
Structured and assessed
First pass (structure_and_assess). Decomposition: the claim is a conditional computational result whose inputs are its load-bearing dependencies. Attached the existing top-quark mass measurement claim (0d485f03) as requires via match_claim; created one new subclaim for the measured Higgs mass near 125 GeV (0306e60c, requires), scored 0.1/contestation 0.02 as settled bedrock, left as a deferred stub per §19. Attached the existing stability-bound claim (b20e4ef7, top pole mass below ~171 GeV) as supports, since the measured central top mass exceeding the bound independently implies a sub-Planckian zero crossing. One natural line of support; no named argument created. Deliberately did NOT attach the sibling claims about top-mass uncertainty (96ddc11c, 2c2fdca9): they bear on the parent metastability question, not on this claim, which is explicitly conditioned on central parameters. Assessment: verified at confidence 0.85, credence 0.92, after checking the primary NNLO literature (Elias-Miró et al. 1112.3022; Degrassi et al. 1205.6497; Buttazzo et al. 1307.3536) via web search: central-value analyses consistently place the MS-bar zero crossing near 10^10 GeV with instability by ~10^11 GeV, matching the claim's range. Marginal yield 0.1: settled technical result, little to gain from a deeper pass. Importance confirmed at 0.3 (contestation 0.15): consequential as a premise of the metastability debate but essentially uncontested itself; the live disputes live in the top-mass claims. Canonical form kept: 16 words, neutral, conditions stated, acceptable to all sides (V, ND, SH, EU applied).
Assessed Verified
verdict confidence 0.85 · credence 0.92
When the Standard Model is extrapolated to high energies by renormalization-group running, the Higgs quartic self-coupling, positive at the electroweak scale, is driven downward by loop effects of the heavy top quark and crosses zero at intermediate energies. Complete next-to-next-to-leading-order analyses, taking as inputs the measured Higgs boson mass near 125 GeV and the directly measured top-quark mass near 172.5 GeV, place the zero crossing at roughly 10^10 GeV, with the resulting instability of the Higgs potential setting in by about 10^11 GeV. The same analyses find that absolute stability would require a top-quark pole mass below about 171 GeV, below the measured central value, which independently confirms that the coupling must turn negative below the Planck scale. The result is conditional on central parameter values, as the claim states. Within current measurement uncertainties, chiefly in the top-quark mass and secondarily in the strong coupling, the crossing scale moves by an order of magnitude or more in either direction, and a sufficiently light top quark would keep the coupling positive up to the Planck scale. The live scientific discussion therefore concerns what the running implies about vacuum stability and how well the top pole mass is known, not the central-value running itself, which is a stable, repeatedly reproduced result of the precision calculations.
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