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arXiv · 1907.06610

Ambiguities of the principle of maximum conformality procedure for hadron collider processes

Herschel A. Chawdhry·Alexander Mitov
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Abstract

In any calculation in perturbative Quantum Chromodynamics (QCD) a choice needs to be made for the unphysical renormalisation scale, $μ_R$. The Brodsky-Lepage-Mackenzie/Principle of Maximum Conformality (BLM/PMC) scale-setting procedure is one proposed method for selecting this scale. In this work we identify three ambiguities in the BLM/PMC procedure itself. Their numerical impact is studied using the example of the total cross-section for $t\bar{t}$ production through Next-to-Next-to-Leading Order in QCD. One ambiguity is the arbitrary choice of the value of the highest-order PMC scale. The numerical impact of this choice on the BLM/PMC prediction for the cross-section is found to be comparable to the impact of the choice of $μ_R$ in the conventional scale-setting approach. Another ambiguity relates to the definitions of the other PMC scales and is similarly found to have a large impact on the cross-section.

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Herschel A. Chawdhry, Alexander Mitov. 2019-10-18. Ambiguities of the principle of maximum conformality procedure for hadron collider processes. https://doi.org/10.1103/physrevd.100.074013

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