Speaker
Description
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 uncertainty is now one of the dominant systematic errors in the recent determination of $\alpha_s(m_Z)$ with the decoupling method by the ALPHA collaboration. In this talk, I will discuss practical improvement conditions to determine $b_g$ non-perturbatively. A perturbative test reproduces the known 1-loop result and first non-perturbative results at parameters required for the alpha_s determination will be shown in a poster by Mattia Dalla Brida.
| Topical area | Standard Model Parameters |
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