Conveners
Standard Model Parameters: Standard Model Parameters I
- Andrea Shindler (Michigan State University)
Standard Model Parameters: Standard Model Parameters II
- Finn Stokes (Forschungszentrum Jülich)
Standard Model Parameters: Standard Model Parameters III
- Gregorio Herdoiza (Instituto de Física Teórica UAM-CSIC)
We determine the strange quark mass and the isospin averaged up/down quark mass from QCD in the isospin limit. We utilize 46 CLS ensembles generated with $N_f=2+1$ non-perturbatively $O(a)$ improved Wilson fermions comprising six lattice spacings in the range $a=0.1$ fm down to $a=0.04$ fm, spatial volumes with $LM_\pi>4$ and pion masses ranging from around 420 MeV down to the physical point....
We present preliminary results for a scale setting procedure based on a mixed action strategy, consisting of Wilson twisted mass valence fermions at maximal twist on CLS ensembles with $N_f=2+1$ flavours of O(a)-improved Wilson sea quarks. Once the matching of valence and sea quark masses is performed, universality tests are carried out by comparing the continuum-limit results of the mixed...
We report on the determination of light quark masses with three sea-quark flavours based on a mixed action with maximally twisted valence fermions on CLS ensembles with O($a$)-improved Wilson sea quarks. The renormalisation and the renormalisation group running over a wide range of scales are based on existing non-perturbative computations in the Schrodinger functional scheme. The...
The decay constants of the kaon and pion provide important input into the determination of light CKM matrix elements. Here we present current progress in computing these quantities using the ensembles and analysis techniques employed by the Budapest-Marseille-Wuppertal collaboration in our recent determination of $a_{\mu}^{LO,HVP}$. This work will provide input on the current 2.6-sigma tension...
We present our calculation of radiative correction to the pion and nucleon decay given by the $\gamma W$ box contribution and needed for the determination of $V_{ud}$.
The pion box contribution is computed on five 2+1+1-flavor HISQ ensembles using with Clover action.
The preliminary nucleon box contribution is being analyzed on one ensemble.
In both contributions, the loop momentum is...
We report on our first set of results for charm physics, using a mixed-action setup with maximally twisted valence fermions on CLS $N_f = 2+1$ ensembles. This setup avoids the need of improvement coefficients to subtract ${\rm O}(am_c)$ effects. The charm quark mass, $D$ and $D_s$ decay constants, and some charmonium observables are computed on a subset of CLS ensembles, which allows to take...
The gradient flow has become a common tool for state-of-the-art lattice
calculations. I will present observations and selected results obtained with the gradient flow.
The gradient flow, which exponentially suppresses ultraviolet field fluctuations and thus removes ultraviolet divergences (up to a multiplicative fermionic wavefunction renormalization), can be used to describe real-space Wilsonian renormalization group transformations and determine the corresponding beta function. We recently proposed a new nonperturbative renormalization scheme for local...
We present new results for the pure gauge SU(3) static force computed in a novel way on the lattice. We use Wilson loops with a chromoelectric field insertion for measuring the force directly and compare it with the traditional way of performing a numerical derivative on the static potential. Extended Wilson loop calculations have a bad signal-to-noise ratio, and the use of discretized chromo...
Integrated time-slice correlation functions $C(t)$ with weights $K(t)$ appear e.g. in
the moments method to determine $\alpha_s$ from heavy quark correlators,
in the muon g-2 determination or in the determination of smoothed spectral
functions. We show that the short distance part of the integral may lead to $\log(a)$-enhanced
discretization errors when $C(t)K(t) \sim t $ for small $t$....
The parametric error on the QCD-coupling can be a dominant source of uncertainty in several important observables. One way to extract the coupling is to compare high order perturbative computations with lattice evaluated moments of heavy quark two-point functions. The truncation of the perturbative series is a sizeable systematic uncertainty that needs to be under control.
In this talk we...
We perform the complete non-perturbative running of the flavour non-singlet
tensor operator from hadronic to elecroweak scales in $N_{f}$= 3
massless QCD, comparing four different definitions of the renormalisation
constant. We use the same configuration ensembles of arXiv:1802.05243,
subject to Schrödinger Functional (SF) boundary conditions, whereas
we use valence quarks with ($\chi$SF)...
We present progress in using momentum-subtraction schemes (RI/MOM and RI/SMOM) to renormalise four-fermion operators, in particular with Wilson fermions. To assess the feasibility and limitations, we study the extraction of renormalisation factors across six different valence actions (including Wilson-Clover and Domain-Wall fermions with and without link smearing). The study uses quenched...
