Heidelberg 2015 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 48: Poster

HK 48.6: Poster

Mittwoch, 25. März 2015, 17:00–19:00, C/Foyer

High precision determination of the weak mixing angle at the future P2-experiment at the MESA-accelerator in Mainz — •Dominik Becker¹, Kathrin Gerz¹, Sebastian Baunack¹, Krishna S. Kumar², and Frank E. Maas^1,3,4 — ¹Institut für Kernphysik, Johannes Gutenberg-Universität Mainz, Germany — ²University of Massachusetts Amherst, Massachusetts, USA — ³GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany — ⁴Helmholtz-Institut Mainz, Johannes Gutenberg-Universität Mainz, Germany

The goal of Project P2 is to determine the electroweak mixing angle sin²(θ_W) to a precision of better than 0.15 % at low momentum transfer (Q² = 0.003 GeV²). The experiment will be carried out at the upcoming MESA accelerator facility in Mainz. MESA is a superconducting energy recovering linear accelerator for electrons up to 155 MeV.

The experimental method comprises a measurement of the proton’s weak charge Q_W^p to a relative uncertainty of 1.9 % via measurement of the parity violating asymmetry in elastic electron-proton scattering. In our poster, we are going to present the experimental method and discuss the achievable precision in the determination of the weak mixing angle. We also show results of Geant4 simulations which were carried out to study the experimental setup. A solenoid magnet with 2 pi azimuthal acceptance will be employed together with a 60 cm hydrogen target. The high luminosity is necessary to get the required statistical precision at the 8 × 10⁻⁹-level.