Heavy Quark Parton Distributions: Mass-Dependent or Mass-Independent Evolution?

Abstract

In a consistently formulated pQCD framework incorporating non-zero mass heavy quark partons, there is still the freedom to define parton distributions obeying either mass-independent or mass-dependent evolution equations, contrary to statements made in a recent paper by MRRS. With properly matched hard cross-sections, different choices merely correspond to different factorization schemes, and they yield the same physical cross-sections. We demonstrate this principle in a concrete order α_s calculation of the DIS charm structure function. We also examine the proper matching between parton definitions and subtractions in the hard cross-section near threshold where the calculation is particularly sensitive to mass effects of the heavy quark. The results obtained from the general-mass formalism are quite stable against different choices of scale and exhibit a smooth transition in the threshold region (using either mass-independent or mass-dependent evolution), in contrast to results of another recently proposed scheme.

6 pages, LaTeX, 4 PostScript figures, uses epsf.sty and aipproc.sty; Contribution to DIS97 Workshop, 14-18 April, Chicago, IL, USA

Cited by in corpus (10)

• A ZEUS next-to-leading-order QCD analysis of data on deep inelastic scattering
• Heavy Quark Hadroproduction in Perturbative QCD
• Single-top production at future ep colliders
• Heavy Quark Production in the ACOT Scheme at NNLO and N3LO
• A Variable Flavour Number Scheme for Heavy Quark Production at Small x
• A Hybrid Scheme for Heavy Flavors: Merging the FFNS and VFNS
• Heavy Quarks: Lessons Learned from HERA and Tevatron
• Treatment of heavy quarks in QCD
• Top-antitop pair production via $b$-quark initiated processes at the Large Hadron Collider
• Mass corrections to the DGLAP equations