Improved perturbation theory for improved lattice actions
Date
2006ISSN
1550-7998Source
Physical Review D - Particles, Fields, Gravitation and CosmologyVolume
74Issue
7Google Scholar check
Metadata
Show full item recordAbstract
We study a systematic improvement of perturbation theory for gauge fields on the lattice the improvement entails resumming, to all orders in the coupling constant, a dominant subclass of tadpole diagrams. This method, originally proposed for the Wilson gluon action, is extended here to encompass all possible gluon actions made of closed Wilson loops any fermion action can be employed as well. The effect of resummation is to replace various parameters in the action (coupling constant, Symanzik coefficients, clover coefficient) by "dressed" values the latter are solutions to certain coupled integral equations, which are easy to solve numerically. Some positive features of this method are (a) it is gauge invariant, (b) it can be applied to improve (to all orders) results obtained at any given order in perturbation theory, (c) it does indeed absorb in the dressed parameters the bulk of tadpole contributions. Two different applications are presented: the additive renormalization of fermion masses, and the multiplicative renormalization ZV (ZA) of the vector (axial) current. In many cases where nonperturbative estimates of renormalization functions are also available for comparison, the agreement with improved perturbative results is consistently better as compared to results from bare perturbation theory. © 2006 The American Physical Society.