https://doi.org/10.1140/epjc/s10052-013-2616-2
Regular Article - Theoretical Physics
Treatment of heavy quarks in QCD
1
Institute for Particle Physics Phenomenology, University of Durham, Durham, DH1 3LE, UK
2
Instituto de Física, Universidade de São Paulo, C.P. 66318, 05315-970, São Paulo, Brazil
3
Petersburg Nuclear Physics Institute, NRC Kurchatov Institute, Gatchina, St. Petersburg, 188300, Russia
* e-mail: A.D.Martin@durham.ac.uk
Received:
26
August
2013
Published online:
25
October
2013
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 
factorization 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 formulas for the explicit m
h
dependence of the splitting functions, and for α
s
, are presented.
© Springer-Verlag Berlin Heidelberg and Società Italiana di Fisica, 2013
