XIIth Quark Confinement and the Hadron Spectrum

A precise determination of the Nf=3 QCD Λ-parameter from lattice QCD

1 Sept 2016, 16:15

15m

Kalliopi (Makedonia Palace)

Section E: QCD and New Physics Section E

Speaker

Mattia Dalla Brida (DESY - Zeuthen)

Description

In this talk we present the ALPHA-collaboration computation of the three-flavour QCD $\mathrm{\Lambda }$-parameter. Starting from the value of $\mathrm{\Lambda }$ in units of an intermediate energy scale $\mu =1/L_0\sim 4\mathrm{G}\mathrm{e}\mathrm{V}$ (cf. talk by S. Sint), we first discuss the connection of this scale and a given hadronic scale, $1/L_{\mathrm{h}\mathrm{a}\mathrm{d}}$, of a few hundred MeV. The latter is obtained very precisely by determining the non-perturbative scale-evolution of the recently proposed gradient flow coupling between these scales. In a second step, $1/L_{\mathrm{h}\mathrm{a}\mathrm{d}}$ is expressed in terms of some measurable hadronic quantity using results from the CLS-collaboration effort. This allows the $\mathrm{\Lambda }$-parameter to be determined in physical units.

Presentation materials

conf12.pdf