Treatment of heavy quarks in QCD

Abstract

We show that to correctly describe the effects of the heavy-quark mass, m_h, in DGLAP evolution, it is necessary to work in the so-called `physical' scheme. In this way, we automatically obtain a smooth transition through the heavy-quark thresholds. Moreover, we show that to obtain NLO accuracy, it is sufficient to account for the heavy-quark mass, m_h, just in the LO (one-loop) splitting function. The use of the MS-bar factorisation scheme is not appropriate, since at NLO we deal with a mixture of quarks and gluon (that is, the mass of the heavy parton is not well-defined). The formulae for the explicit m_h dependence of the splitting functions, and for alpha_s, are presented.

14 pages, 3 figures, references updated, version to be published in EPJC

References in corpus (5)

• Parton distributions for the LHC
• The CT10 NNLO Global Analysis of QCD
• Heavy-quark mass dependence in global PDF analyses and 3- and 4-flavour parton distributions
• PQCD Formulations with Heavy Quark Masses and Global Analysis
• Treatment of the infrared contribution: NLO QED evolution as a pedagogic example

Cited by in corpus (6)

• Uncertainties on ${\alpha }_S$ in the MMHT2014 global PDF analysis and implications for SM predictions
• QCD and Jets at Hadron Colliders
• Measurements of groomed-jet substructure of charm jets tagged by ${\mathrm{D}}^0$ mesons in proton-proton collisions at $\sqrt{s}$ = 13 TeV
• Physical factorisation scheme for PDFs for non-inclusive applications
• Inclusive photoproduction of bottom quarks for low and medium pT in the general-mass variable-flavour-number scheme
• Mass corrections to the DGLAP equations