[en] A series of approved nucleon structure experiments that utilize a new spectrometer called Super-BigBite for Jefferson Lab experimental Hall A after the 12 GeV upgrade will be presented. These experiments will obtain unprecedented measurements of the internal quark structure of nucleons by measuring the three electromagnetic form factors, GpE, GnE, and GnM, and the single-spin asymmetry in semi-inclusive deep inelastic scattering on a polarized 3He nucleus. At the core of these experiments is the Super-BigBite spectrometer, a non-focusing large angular and momentum acceptance spectrometer that is designed to operate in environments of high luminosity up to ∼ 10³⁸ Hz=cm2 and to be highly reconfigurable to meet a wide range of experimental needs. The large acceptance of the spectrometer allows for these experiments to obtain statistical precisions comparable to or better than previous measurements. This also allows for the form factor measurements to be carried out to unprecedentedly high Q2. An overview the upcoming experimental program goals and hardware in development will be presented.

[en] The electric and magnetic form factors of the nucleon provide experimental access to the underlying charge and magnetic moment distributions of quarks. We have measured the electric form factor of the neutron at four kinematic points between 1.2 and 3.5 GeV² in Hall A at Jefferson Lab. This more than doubles the momentum transfer region for which this quantity has previously been measured, providing new information on the structure of the neutron. Preliminary results for Gⁿ_E at Q² = 1.7, 2.5, and 3.5 GeV² were presented and were compared with QCD-based models and phenomenological approaches.

[en] We describe the research and development work for the P2 experiment which aims for a high precision determination of the weak mixing angle sin² θ_W to a precision of 0.15% at a four-momentum transfer of 4.5 x 10^-3 GeV². This accuracy, comparable to existing measurements at the Z pole, allows for a sensitive test of the Standard Model up to a mass scale of 50 TeV, extendable to 60 TeV. The weak mixing angle is connected to the weak charge of the proton which will be extracted from a measurement of the parity violating cross section asymmetry -39.94 x 10^-9 in elastic electron-proton scattering. A total accuracy of 0.57 x 10^-9 is achievable in a measurement time of 11000 h using a 150 μA polarized electron beam impinging on a 60 cm liquid hydrogen target. The P2 asymmetry is smaller than any asymmetry measured so far in electron scattering with an unprecedented goal for the accuracy. The use of a solenoid spectrometer with 100% φ-acceptance as well as an atomic hydrogen trap polarimeter are new features, which have never before been used in parity-violation experiments. In order to collect the enormous statistics required for this measurement, the new Mainz Energy-Recovering Superconducting Accelerator (MESA) is under construction. Plans for the associated beam control system and the polarimetry are described in this article as well. A liquid hydrogen high-power target with an extremely low noise level of 10 ppm needs to be designed and constructed. We report in addition 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. The physics program of the MESA facility comprises indirect, high precision search for physics beyond the Standard Model, measurement of the neutron distribution in nuclear physics, single-spin asymmetries, and a possible future extension to the measurement of hadronic parity violation. (orig.)