The P2 Experiment - A future high-precision measurement of the electroweak mixing angle at low momentum transfer
Creators: name: Becker, Dominik
name: Bucoveanu, Razvan
name: Grzesik, Carsten
name: Kempf, Ruth
name: Imai, Kathrin
name: Molitor, Matthias
name: Tyukin, Alexey
name: Zimmermann, Marco
name: Armstrong, David
name: Aulenbacher, Kurt
name: Baunack, Sebastian
name: Beminiwattha, Rakitha
name: Berger, Niklaus
name: Bernhard, Peter
name: Brogna, Andrea
name: Capozza, Luigi
name: Dusa, Silviu Covrig
name: Deconinck, Wouter
name: Diefenbach, Jürgen
name: Erler, Jens
name: Gal, Ciprian
name: Gläser, Boris
name: Gou, Boxing
name: Gradl, Wolfgang
name: Gericke, Michael
name: Gorchtein, Mikhail
name: Imai, Yoshio
name: Kumar, Krishna S.
name: Maas, Frank
name: Mammei, Juliette
name: Pan, Jie
name: Pandey, Preeti
name: Paschke, Kent
name: Perić, Ivan
name: Pitt, Mark
name: Rahman, Sakib
name: Riordan, Seamus
name: Piñeiro, David Rodríguez
name: Sfienti, Concettina
name: Sorokin, Iurii
name: Souder, Paul
name: Spiesberger, Hubert
name: Thiel, Michaela
name: Tyukin, Valery
name: Weitzel, Quirin
Publisher: name: arXiv
Year: 2018
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: High Energy Physics - Experiment (hep-ex)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: This article describes the future P2 parity-violating electron scattering facility at the upcoming MESA accelerator in Mainz. The physics program of the facility comprises indirect, high precision search for physics beyond the Standard Model, measurement of the neutron distribution in nuclear physics, single-spin asymmetries stemming from two-photon exchange and a possible future extension to the measurement of hadronic parity violation. The first measurement of the P2 experiment aims for a high precision determination of the weak mixing angle to a precision of 0.14% at a four-momentum transfer of Q^2 = 4.5 10^{-3} GeV^2. The accuracy is comparable to existing measurements at the Z pole. It comprises a sensitive test of the standard model up to a mass scale of 50 TeV, extendable to 70 TeV. This requires a measurement of the parity violating cross section asymmetry -39.94 10^{-9} in the elastic electron-proton scattering with a total accuracy of 0.56 10^-9 (1.4 %) in 10,000 h of 150 \micro A polarized electron beam impinging on a 60 cm liquid H_2 target allowing for an extraction of the weak charge of the proton which is directly connected to the weak mixing angle. Contributions from gamma Z-box graphs become small at the small beam energy of 155 MeV. The size of the asymmetry is the smallest asymmetry ever measured in electron scattering with an unprecedented goal for the accuracy. We report here on the conceptual design of the P2 spectrometer, its Cherenkov detectors, the integrating read-out electronics as well as the ultra-thin, fast tracking detectors. There has been substantial theory work done in preparation of the determination of the weak mixing angle. The further physics program in particle and nuclear physics is described as well.
description: Invited EPJ A Manuscript, many figures, large file size