出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：Quark currents renormalization constants can in principle be safely computed in lattice perturbation
theory. In practice, traditional lattice perturbative computations are quite cumbersome,
so that so far only the first loop results were available. By making use of Numerical Stochastic
Perturbation Theory we reached three (and with less statistical precision even four) loops, both
in quenched and in unquenched theory. Convergence properties of the series can be assessed and
comparison with non perturbative results (where available) can be made: high loops computations
of renormalization constants can be a valuable tool for lattice QCD.
