The future μCLAS12 experiment at Jefferson Lab (USA) will study the nucleon structure through high-statistics measurements of di-muon electro- and photo-production. Its primary physics goal is Double Deeply Virtual Compton Scattering (DDVCS), ep→e’p’µ+µ–, which will allow, for the first time, a multidimensional mapping of the Generalized Parton Distributions (GPDs). Additionally, large statistics Timelike Compton Scattering (TCS) and Near-threshold J/ψ production measurements will be performed with the same setup. Overall, this upgrade has the potential to greatly improve knowledge of both the quark and the gluon content of the proton. For this reason, μCLAS12 has been awarded 245 days of data-taking by the Jefferson Lab PAC in July 2025.
Achieving these challenging measurements requires a major upgrade of the CLAS12 experiment. The forward detector of CLAS12 will effectively be converted into a large-acceptance muon spectrometer, with the addition of a lead shield. Four new detector systems, namely a PbWO₄ Forward Calorimeter, a six-layer Forward Vertex Tracker, a Recoil Vertex Detector and a central scintillation hodoscope, will allow the detection of scattered electrons and recoil nucleons. The design of these detectors is driven by the high-luminosity envisioned during the operation of μCLAS12 (1037 cm⁻²s⁻¹). This presentation will also include a complete description of the Geant4 simulations which have been performed to estimate the required performances of the planned new detector systems.
DPhN