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

Precision determination of the strong coupling at the electroweak scale

25 Jul 2016, 17:25
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. Rainer Sommer (NIC @ DESY)

Description

The ALPHA-collaboration computation of the three-flavor Lambda-parameter and the determination of $\alpha(m_Z)$ consists of the steps: Running from beyond the Z-mass to 4 GeV in the SF scheme, matching to the GF scheme, running from 4GeV to small energy in the GF scheme, determining the smallest energy scale ($\approx$ 200 MeV) in physical units with the help of the CLS simulations. We summarize the first steps and discuss the last one in detail. We then present our final result for $\Lambda_{\rm \overline{MS}}^{(3)}$ with its error budget. Finally, the connection of the three-flavor theory to the five-flavor $\alpha(m_Z)$ uses decoupling and high order perturbation theory in the $\rm \overline{MS}$ scheme.

Primary author

Prof. Rainer Sommer (NIC @ DESY)

Co-authors

Dr Alberto Ramos (CERN) Dr Hubert Simma Dr Mattia Bruno (Brookhaven Natl. Lab.) Dr Mattia Dalla Brida (DESY - Zeuthen) Dr Patrick Fritzsch Stefan Schaefer (NIC, DESY) Prof. Stefan Sint (Trinity College Dublin) Dr Tomasz Korzec (Bergische Universität Wuppertal)

Presentation Materials