Lattice2010

Session

Parallel 32: Standard model parameters and renormalization

15 Jun 2010, 16:40

Villasimius, Sardinia

128. Ghost-gluon coupling power corrections and $\Lambda_{\overline{MS}}$ from twisted-mass lattice QCD at $N_f=2$.

Mario Gravina (LPT - Universite Paris 11, Orsay (France))

15/06/2010, 16:40

Standard model parameters and renormalization

I present results concerning the non-perturbative evaluation of the ghost-gluon running QCD coupling constant from $N_f=2$ twisted-mass lattice calculations. Special attention is payed to the treatment of artifacts, in particular the quark mass, and to the different sources of systematical uncertainties. The value of $\Lambda_{\overline{MS}}$ is computed revealing the presence of a...

85. Running of the Schroedinger functional coupling with four massless flavours

Rainer Sommer (NIC, DESY)

15/06/2010, 17:00

Standard model parameters and renormalization

I discuss the status of different determinations of alpha_s, motivating a precise and reliable computation from lattice QCD. In order to suppress perturbative errors, the non-perturbative computation has to reach high energy scales mu. Such results already exist in the SF-scheme for Nf=0,2,3 . We now add the running with four massless flavours in a range of alpha from about 0.07 to 0.3...

229. Non-perturbative running of the coupling from four-flavour lattice QCD with staggered quarks

Paula Perez Rubio (Universidad Autonoma de Madrid and Trinity College Dublin)

15/06/2010, 17:20

Standard model parameters and renormalization

Using the Schroedinger functional (SF) with a single staggered fermion field we calculate the SF coupling in four-flavour QCD for a wide range of energies and lattice sizes up to $L/a=16$. Preliminary results for the continuum extrapolation of the step-scaling function are presented. To reduce cutoff effects, one-loop ${\rm O}(a)$ improvement has been implemented. Various cross checks...