24-30 July 2016
Highfield Campus, University of Southampton
Europe/London timezone

On the accuracy of perturbation theory in QCD

25 Jul 2016, 16:45
20m
Building 67 Room 1007 (Highfield Campus, University of Southampton)

Building 67 Room 1007

Highfield Campus, University of Southampton

Talk Standard Model Parameters and Renormalization Standard Model Parameters and Renormalization

Speaker

Prof. Stefan Sint (Trinity College Dublin)

Description

A collaborative effort to determine the $\Lambda$-parameter in 3-flavour QCD by the ALPHA collaboration is currently being finalized. The strategy involves 2 finite volume schemes for the coupling, both defined with Schroedinger functional (SF) boundary conditions. I here discuss the scale evolution from an intermediate scale $1/L_0$ of about 4 GeV to scales of O(100) GeV using the traditional SF coupling and a 1-parameter family of close relatives. Our precise continuum extrapolated data allows for stringent tests of perturbation theory, which is then used to extract $L_0*\Lambda$ with an error below 3 per cent. To quote such a small error with confidence, non-perturbative data is required around alpha_s = 0.1. In particular, we have evidence that the apparent precision reached with data around alpha_s = 0.2 can be misleading. (cf. related talks by A. Ramos and R. Sommer)

Primary authors

Dr Alberto Ramos (CERN) Dr Mattia Dalla Brida (DESY - Zeuthen) Dr Patrick Fritzsch (IFT, UAM/CSIC, Universidad Autonoma de Madrid) Prof. Rainer Sommer (NIC @ DESY) Prof. Stefan Sint (Trinity College Dublin) Dr Tomasz Korzec (Bergische Universität Wuppertal)

Presentation Materials

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