Michele Brambilla
(Parma University and INFN)
14/06/2010, 14:30
Standard model parameters and renormalization
The Numerical Stochastic Perturbation Theory project dealing with renormalization constants for the tree level Symanzik improved gauge action aims at three loop accuracy. To get this, one important ingredient is the two loop matching of the lattice coupling to continuum. We discuss how we get it, trying to emphasize the general strategy underlying the computation.
David Palao
(INFN Sezione Tor Vergata)
14/06/2010, 14:50
Standard model parameters and renormalization
We report about an ongoing non-perturbative computation of RI-MOM scheme renormalization constants for
the lattice action with Iwasaki glue and four dynamical flavours currently in use by ETMC.
For this goal dedicated simulations with four degenerate sea quark flavours
are performed at several values of the standard and twisted quark mass parameters. We discuss a
method for removing...
Yusuke Taniguchi
(University of Tsukuba)
14/06/2010, 15:10
Standard model parameters and renormalization
We present an evaluation of the quark mass renormalization factor for
Nf=2+1 QCD.
The Schroedinger functional scheme is used as the intermediate scheme.
The regularization independent step scaling function of the quark mass
is evaluated in the continuum limit.
The pseudo scalar density and the axial vector current renormalization
factors are derived for the same action and the bare...
Francesco Di Renzo
(University of Parma and INFN)
14/06/2010, 15:30
Standard model parameters and renormalization
Comparing perturbative and non-perturbative results for renormalization constants has been an issue for a while. The quark mass renormalization constant is a prototype example: discrepancies between different results have been several times ascribed to this issue. Given the logarithmic nature of the divergence, there is no theoretical obstruction to a perturbative computation. The problem, as...
Konstantin Petrov
(Laboratoire de Physique Theorique)
14/06/2010, 15:50
Standard model parameters and renormalization
We present our results on non-perturbative renomalization of quark operators. Based on Nf=2 ETMC lattices we calculate vertex functions and propagators, and combine them using irreducible representation of the discrete rotational group H4. We test the running of these quantities including a possible non-perturbative contribution via Wilson operator expansion. This allows for the better...
