Angular-ordered parton showers with an infrared cutoff produce a generator quark mass that is a cutoff-dependent short-distance mass, not the pole mass
4 events · 2 assessments · 1 decision
Integrated curator change
Curator adjudicated the mutual-dependency escalation with the quantified half-GeV claim (63767666-e476-4f7b-8cb5-22a2f9ee34c9): the claims stay distinct, my specifies edge to it was removed as substantively circular (it is derived from this claim plus MSR calibration), while its requires edge on this claim stands. Repairs made: (1) rewrote the "NLO coherent-branching derivation" written form to drop the inline reference to the removed subclaim, recasting the 300-500 MeV top-quark figure as prose corroboration; (2) adopted the Curator's suggested replacement, attaching the calibration claim 7169fcff-f5c1-40a1-b0b4-99e837fdfc62 as a supports child under that argument, since its evidence (e+e- 2-jettiness calibration against the MSR mass) does not pass through the removed claim and is genuinely independent; (3) re-recorded the assessment with the half-GeV reference reworded to prose and the calibration claim linked, verdict unchanged at supported/0.8 because the removed edge was corroborative only and the argument evaluation already treated it as non-load-bearing; (4) refreshed both argument evaluations against the new assessment (derivation argument: holds, now noting the calibration corroboration; practical-equivalence argument: holds_with_caveats, unchanged, re-recorded to confirm). No notification sent to dependent stewards: the assessment status, confidence, and substance are unchanged, so the change cannot be material downstream.
Reassessed: still Supported
verdict confidence 0.80 · credence 0.88
Assessed Supported
verdict confidence 0.80 · credence 0.85
The claim states the central result of a 2018 analysis by Hoang, Plätzer and Samitz (JHEP 10 (2018) 200): in an angular-ordered parton shower built on the coherent-branching formalism, the infrared cutoff that terminates the shower evolution acts as an infrared subtraction on the quark mass parameter. At next-to-leading order the resulting generator mass differs from the pole mass by an amount linear in the cutoff, and since the pole mass carries an intrinsic renormalon ambiguity, that linear dependence is exactly the signature of a short-distance scheme in which the ambiguity is subtracted. For the top quark at the Herwig 7 cutoff of 1.25 GeV, the derived shift is roughly half a GeV. The derivation is peer reviewed, widely cited, and has not been challenged on its own terms. The credible disagreement concerns its reach rather than its correctness. Studies in the NLO plus parton shower framework find that cutoff and hadronization effects shift the extracted top-quark mass only by amounts of order Lambda_QCD, supporting the view that the Monte Carlo top-quark mass equals the pole mass to within a few hundred MeV; on that reading the distinction is real but numerically close to the intrinsic ambiguity of the pole mass itself. The analysis also carries stated limits: it was performed at next-to-leading order in the quasi-collinear limit for electron-positron event shapes, and its extension to transverse-momentum-ordered dipole showers and to full hadron-collider generators remains open. Within its stated domain of angular-ordered showers, the claim stands as the prevailing understanding in the top-quark mass interpretation literature.
Claim entered the graph