Origin of discrepancies between resummation-space calculations

Resolve the origin of the discrepant numerical predictions for thrust obtained in different resummation spaces and formalisms, particularly the large direct-space versus conjugate-space differences reported by Aglietti et al., so that the associated perturbative uncertainty can be reliably assessed.

Background

Thrust resummation can be formulated in direct momentum space or in a conjugate Laplace space. These formulations are formally equivalent at a fixed logarithmic accuracy, differing only through terms beyond the nominal accuracy, so their residual numerical difference should decrease with increasing perturbative order when perturbation theory is reliable.

The paper reports conflicting results: one calculation found differences as large as approximately 20% in the conventional thrust fit region, whereas two independent analyses found substantially smaller differences that decreased with perturbative accuracy and were covered by their perturbative uncertainty estimates. The meeting did not determine which ingredients or implementation choices caused this discrepancy, motivating an ingredient-by-ingredient benchmark comparison.