Dark sectors 2016 Workshop: community report

This report, based on the Dark Sectors workshop at SLAC in April 2016, summarizes the scientific importance of searches for dark sector dark matter and forces at masses beneath the weak-scale, the status of this broad international field, the important milestones motivating future exploration, and promising experimental opportunities to reach these milestones over the next 5-10 years

Electron elastic scattering off a Tensor-polarized Deuterium Internal Target

The tensor analyzing power Γ20 in elastic electron-deuteron scattering has been measured in the four momentum transfer region between 1.4 and 3.2 fm~l using the Internal Target Facility at NIKHEF. Tensor-polarized deuterium is produced in an Atomic Beam Source and injected into a storage cell. Scattered electrons and recoil deuterons were detected in coincidence with two large acceptance nonmagnetic detectors

The role of final-state interaction in tensor polarization effects of the reaction γd→pnπ0\gamma d \rightarrow p n \pi ^{0} γ d → p n π 0

Abstract Tensor analyzing-power components $$T_{20}$$ T 20 , $$T_{21}$$ T 21 , and $$T_{22}$$ T 22 for the reaction $$\gamma d\rightarrow np\pi ^0$$ γ d → n p π 0 have been studied for the first time in the photon energy range from 280 to 500 MeV. The data are extracted from the experimental statistics accumulated at the VEPP-3 storage ring in 2002–2003. The measured asymmetries are compared with the results of statistical simulations performed with the $$\gamma d\rightarrow np\pi ^0$$ γ d → n p π 0 amplitude from a spectator model, taking into account corrections for the final-state interaction. The comparison demonstrates quite good agreement between the experimental results and the theory

Measurement of the Tensor-Analyzing Power Component <i>T</i>₂₀ for Incoherent Negative Pion Photoproduction on a Deuteron

New results for the T20-component of the tensor-analyzing power of the incoherent negative pion photoproduction are presented. The experiment was performed for the electron beam energy of 800 MeV at the VEPP-3 storage ring in 2021. To extract the T20-component, we used asymmetry with respect to the change in the sign of the tensor polarization of the deuteron target. Identification of the reaction events was carried out by the detection of two protons in coincidence. Experimental data were compared with the results of statistical simulation, considering the interaction between the NN and πN subsystems in the final state of the reaction