Conveners
Standard Model Parameters
- Andrew Lytle (University of Illinois, Urbana-Champaign)
We determine the scales $r_0$, $r_1$, and the ratio $r_0/r_1$ for 2 + 1 flavour QCD ensembles generated by CLS. These scales are determined from an improved definition of the static force which we measure using Wilson loops and furthermore use to study the shape of the static potential. Our analysis involves various continuum and chiral extrapolations of data that covers pion masses between...
Lattice QCD with Wilson quarks near the continuum limit can be described by Symanzik's effective continuum action which contains the dimension 5 operator, $m \,tr(F_{\mu\nu}F_{\mu\nu})$. Its effect can be eliminated by an O$(am)$ rescaling of the bare lattice coupling constant.The corresponding improvement coefficient, $b_g$, is currently only known to 1-loop order and the resulting...
We present a first numerical implementation of a massive nonperturbative renormalisation scheme, RI/mSMOM, in the study of heavy quarks using the domain-wall fermion action. In particular, we calculate renormalisation constants for fermion bilinears at non-vanishing heavy quark masses and compare the approach to the continuum of the renormalised charm quark mass with that from a...
We report on the ongoing effort of improving the determination of the gradient flow scale on the 2+1+1 HISQ ensembles generated by the MILC collaboration. We measure the $t_0$ and $w_0$ scales with the Wilson and Symanzik flow using three discretizations for the action density: clover, Wilson and tree-level Symanzik-improved. For the absolute scale setting we intend to employ the Omega baryon...
We carry out a scale setting procedure of a mixed action setup
consisting of valence Wilson twisted mass fermions at maximal twist on
CLS ensembles with $N_f=2+1$ flavours of $O(a)$-improved Wilson sea
quarks. We determine the gradient flow scale $t_0$ using pion and kaon
isoQCD masses and decay constants as external input. We employ model
variation techniques to probe the systematic...
We measure the static force directly by inserting chromo electric fields into the Wilson loop. We use the gradient flow to improve the signal-to-noise ratio, and to renormalize the field components. Furthermore, we can perform the continuum and zero flow time limit, obtaining a first direct determination of the QCD static force.
By comparing the lattice result with a perturbative calculation...