Dresden 2013 – wissenschaftliches Programm

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T: Fachverband Teilchenphysik

T 22: Gittereichtheorie

T 22.1: Vortrag

Montag, 4. März 2013, 16:45–17:00, WIL-C129

Leading-order hadronic contributions to a_µ and α_QED from N_f=2+1+1 twisted mass fermions — Xu Feng¹, •Grit Hotzel², Karl Jansen³, Marcus Petschlies⁴, and Dru Renner⁵ — ¹High Energy Accelerator Research Organization (KEK), Tsukuba, Japan — ²Humboldt-Universität zu Berlin, Institut für Physik, Berlin, Germany — ³NIC, DESY, Zeuthen, Germany — ⁴The Cyprus Institute, Nicosia, Cyprus — ⁵Jefferson Lab, Newport News, USA

We present the first four-flavour lattice calculation of the leading-order hadronic vacuum-polarisation contribution to the anomalous magnetic moment of the muon, a_µ^hvp, and the hadronic running of the QED coupling constant, Δ α_QED^hvp (Q²).

In the heavy sector a mixed-action setup is employed. The bare quark masses are determined from matching the K- and D-meson masses to their physical values. Several light quark masses are used in order to yield a controlled extrapolation to the physical pion mass by utilising a recently proposed improved method. We demonstrate that this method also works in the four-flavour case.