Two-loop calculation of the anomalous dimension of the axial current with static heavy quarks
1992; Elsevier BV; Volume: 375; Issue: 3 Linguagem: Inglês
10.1016/0550-3213(92)90112-o
ISSN1873-1562
Autores Tópico(s)High-Energy Particle Collisions Research
ResumoA method to perform two-loop calculations in Eichten's effective field theory for heavy quarks is developed. The anomalous dimension of the axial current for static heavy quarks is calculated at two loops. For N = 3, we get γA(2) = −136[1272+28ξ(2)−5Nf]. This result is very important to understand completely the physical significance of the lattice measurement of the decay constant of the B meson. The two-loop correction generated by γA(2) turns out to be small, less than 1% for four quark flavours, so that the value of the decay constant of the B meson does not need in practice renormalization group improvement. As extra results, the self-energy renormalization constant at two-loop level for a heavy static quark and that for the coupling of a heavy quark to a gluon are obtained.
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