Mainz 2022 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 32: Hadron Structure and Spectroscopy VI
HK 32.4: Talk
Tuesday, March 29, 2022, 17:00–17:15, HK-H9
Electromagnetic form factors of the nucleon in Nf = 2 + 1 lattice QCD — Dalibor Djukanovic1,2, Georg von Hippel3, Harvey B. Meyer1,2,3, Konstantin Ottnad3, •Miguel Salg3, Jonas Wilhelm3, and Hartmut Wittig1,2,3 — 1Helmholtz Institute Mainz, Staudingerweg 18, 55128 Mainz, Germany — 2GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany — 3PRISMA+ Cluster of Excellence and Institute for Nuclear Physics, Johannes Gutenberg University of Mainz, Johann-Joachim-Becher-Weg 45, 55128 Mainz, Germany
We present results for the electromagnetic form factors of the nucleon computed on the Coordinated Lattice Simulations (CLS) ensembles with Nf = 2 + 1 flavors of O(a)-improved Wilson fermions and an O(a)-improved conserved vector current. From the Q2-dependence of the form factors, we determine the electric and magnetic charge radii and the magnetic moment of the proton. In order to estimate the excited-state contamination, we employ several source-sink separations and apply the summation method. The quark-disconnected diagrams entering into the isoscalar quantities are computed explicitly. For this purpose, a stochastic estimation based on the one-end trick is performed, in combination with a frequency-splitting technique and the hopping parameter expansion. By these means, we obtain a clear signal for the form factors including the quark-disconnected contributions, which have a statistically significant effect on our results.