The P2 Experiment - A future high-precision measurement of the electroweak mixing angle at low momentum transfer

Abstract

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.

arXiv commentInvited EPJ A Manuscript, many figures, large file size

References in corpus (80)

• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• Measurement of the Neutron Radius of 208Pb Through Parity-Violation in Electron Scattering
• Complete electric dipole response and the neutron skin in 208Pb
• Neutron skins and neutron stars in the multi-messenger era
• Neutron skin of 208Pb, nuclear symmetry energy, and the parity radius experiment
• Parity Violating Measurements of Neutron Densities
• Constraints on the symmetry energy and on neutron skins from the pygmy resonances in 68Ni and 132Sn
• Intermediate-Energy Semileptonic Probes of the Hadronic Neutral Current
• Precision Measurement of the Weak Mixing Angle in Moller Scattering
• Strange Quark Contributions to Parity-Violating Asymmetries in the Forward G0 Electron-Proton Scattering Experiment
• "Dark" Z implications for Parity Violation, Rare Meson Decays, and Higgs Physics
• Neutron skin of ${}^{208}$Pb from Coherent Pion Photoproduction
• Weak mixing angle at low energies
• Measurement of Strange Quark Contributions to the Nucleon's Form Factors at Q^2=0.230 (GeV/c)^2
• The Strange Quark Contribution to the Proton's Magnetic Moment
• Precision Measurements of the Nucleon Strange Form Factors at Q^2 ~0.1 GeV^2
• Parity-violating electroweak asymmetry in $\vec{e}p$ scattering
• Muon g-2, Rare Kaon Decays, and Parity Violation from Dark Bosons
• Evidence for Strange Quark Contributions to the Nucleon's Form Factors at $Q^2$ = 0.108 (GeV/c)${}^2$
• Measurement of the Proton's Neutral Weak Magnetic Form Factor
• Parity-Violating Electron Scattering from 4He and the Strange Electric Form Factor of the Nucleon
• Constraints on the Nucleon Strange Form Factors at Q^2 ~ 0.1 GeV^2
• First Determination of the Weak Charge of the Proton
• Low Energy Precision Test of Supersymmetry
• Measurement of the Neutral Weak Form Factors of the Proton
• Strange Quark Contributions to Parity-Violating Asymmetries in the Backward Angle G0 Electron Scattering Experiment
• Dark Sectors 2016 Workshop: Community Report
• Low Energy Measurements of the Weak Mixing Angle
• Measurement of Strange Quark Contributions to the Vector Form Factors of the Proton at Q**2=0.22 (GeV/c)**2
• Parity Violation in Elastic Electron-Proton Scattering and the Proton's Strange Magnetic Form Factor
• The Weak Charge of the Proton and New Physics
• General Broken Lines as advanced track fitting method
• Parity-violating Electron Deuteron Scattering and the Proton's Neutral Weak Axial Vector Form Factor
• Low-Energy Parity-Violation and New Physics
• New Measurement of Parity Violation in Elastic Electron-Proton Scattering and Implications for Strange Form Factors
• Observation of Parity Nonconservation in Moller Scattering
• Measurement of the vector analyzing power in elastic electron-proton scattering as a probe of double photon exchange amplitudes
• A Global Fit to Extended Oblique Parameters
• Measurement of the Transverse Beam Spin Asymmetry in Elastic Electron Proton Scattering and the Inelastic Contribution to the Imaginary Part of the Two-Photon Exchange Amplitude
• New Precision Limit on the Strange Vector Form Factors of the Proton
• Global Analysis of Nucleon Strange Form Factors at Low $Q^2$
• Electroweak Measurements of Neutron Densities in CREX and PREX at JLab, USA
• Strange nucleon form factors in the perturbative chiral quark model
• Model-dependence of the $\gamma Z$ dispersion correction to the parity-violating asymmetry in elastic $ep$ scattering
• Dispersion $\gamma Z$-box correction to the weak charge of the proton
• Resonance estimates for single spin asymmetries in elastic electron-nucleon scattering
• gamma-Z corrections to forward-angle parity-violating e-p scattering
• Weak Mixing Angle in the Thomson Limit
• Isospin violation in the vector form factors of the nucleon
• New Measurements of the Transverse Beam Asymmetry for Elastic Electron Scattering from Selected Nuclei
• Strange magnetic form factor of the proton at $Q^2=0.23$ GeV${}^2$
• Fast alignment of a complex tracking detector using advanced track models
• Polarized Moller Scattering Asymmetries
• New formulation of gamma-Z box corrections to the weak charge of the proton
• Gamma-Z box contributions to parity violating elastic e-p scattering
• The MOLLER Experiment: An Ultra-Precise Measurement of the Weak Mixing Angle Using Møller Scattering
• Weak Polarized Electron Scattering
• A New Paradigm for Hadronic Parity Nonconservation and its Experimental Implications
• Violations of discrete space-time symmetries in chiral effective field theory
• Transverse Beam Spin Asymmetries in Forward-Angle Elastic Electron-Proton Scattering
• The MuPix System-on-Chip for the Mu3e Experiment
• Transverse Beam Spin Asymmetries at Backward Angles in Elastic Electron-Proton and Quasi-elastic Electron-Deuteron Scattering
• Measurements and simulations of Cherenkov light in lead fluoride crystals
• Global analysis of parity-violating asymmetry data for elastic electron scattering
• The G0 Experiment: Apparatus for Parity-Violating Electron Scattering Measurements at Forward and Backward Angles
• Measuring the P-odd Pion-Nucleon Coupling h_{πNN}^{(1)} in π^+ Photoproton Production Near the Threshold
• Parity-Violating Pion-Nucleon Coupling h_{πNN}^{(1)} from π^+ Electroproton Production Near the Threshold
• Quark-hadron duality constraints on γZ box corrections to parity-violating elastic scattering
• The Cryogenic Target for the G${}^0$ Experiment at Jefferson Lab
• On the two-boson exchange corrections to parity-violating elastic electron-proton scattering
• Realtime calibration of the A4 electromagnetic lead fluoride calorimeter
• A high power liquid hydrogen target for the Mainz A4 parity violation experiment
• Subleading corrections to parity violating pion photoproduction
• Irradiation study of a fully monolithic HV-CMOS pixel sensor design in AMS 180 nm
• Multiple Coulomb Scattering in Thin Silicon
• How strange is pion electroproduction?
• A luminosity monitor for the A4 parity violation experiment at MAMI
• Measurement of the parity-violating asymmetry in inclusive electroproduction of ${\pi }^{-}$ near the ${\Delta }^0$ resonance
• Evaluation of theoretical uncertainties in parity-violating electron scattering from nucleons and nuclei
• Hadronic weak charges and parity-violating forward Compton scattering

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• QED at NNLO with McMule
• First-Generation New Physics in Simplified Models: From Low-Energy Parity Violation to the LHC
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