Speaker
Stefan Sint
(Trinity College Dublin)
Description
The ALPHA collaboration has set itself the goal to determine alpha_s(m_Z) with a total error substantially below the percent level. A further step towards this goal can be taken by combining results from the recent simulations of 2+1 flavour QCD by the CLS initiative with a number of tools developed over the years: renormalized couplings in finite volume schemes, recursive finite size techniques, two-loop renormalized perturbation theory and the (improved) gradient flow on the lattice. I will sketch the strategy, which involves both the standard SF coupling in the high energy regime and a gradient flow coupling at low energies. This implies the need for matching both schemes at an intermediate switching scale. Our results for the scale evolution at high energies allow for a well-controlled continuum limit and thus yield the Nf=3 Lambda-parameter in units of this switching scale. Simulations at lower energy scales are underway. I will present first results for the scale evolution of a gradient flow coupling with SF boundary conditions.
Primary authors
Alberto Ramos
(CERN)
Mattia Dalla Brida
(NIC@DESY-Zeuthen)
Patrick Fritzsch
(Instituto de Física Teoríca UAM/CSIC)
Rainer Sommer
(NIC@DESY-Zeuthen)
Stefan Sint
(Trinity College Dublin)
Tomasz Korzec
(Humboldt-University Berlin)
