Matching heavy-quark fields in QCD and HQET at three loops
arXiv:1004.2662 · doi:10.1016/j.physletb.2010.07.032
Abstract
The relation between the heavy-quark field in QCD and the corresponding field in HQET is derived up to three loops, and to all orders in the large- limit. The corresponding relation between the QED electron field and the Bloch--Nordsieck one is gauge invariant to all orders. We also prove that the anomalous dimension of the QED electron field depends on the gauge parameter only at one loop.
9 pages, no figures. v2: discussion of gauge invariance in QED extended, references added; v3: QED gauge invariance completely proved; v4: 1 reference added; v5: several typos in the Appendix fixed