出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We present an update on Numerical Stochastic Perturbation Theory projects for Lattice QCD,
which are by now run on apeNEXT. As a first issue, we discuss a strategy to tackle finite size
effects which can be quite sizeable in the computation of logarithmically divergent renormalization
constants. Our first high loop determination of quark bilinears for Wilson fermions was
limited to finite constants and finite ratios. A precise determination of ZP and ZS (and hence of
Zm) now becomes possible. We also give an account of computations for actions different from
the standard regularization we have taken into account so far (Wilson gauge action and Wilson
fermions). In particular, we present the status of computations for the Lattice QCD regularization
defined by tree level Symanzik improved gauge action andWilson fermions, which became quite
popular in recent times. We also take the chance to discuss the related topic of the computation of
the gluon and ghost propagators (which we undertook in collaboration with another group). This
is relevant in order to better understand non-perturbative computations of propagators aiming at
qualitative/quantitative understanding of confinement.
