Speaker
Description
The Mainz Energy-Recovery Superconducting Accelerator (MESA), to be commissioned in 2027, will enable precision experiments in nuclear, hadron, and particle physics. We report on the physics program of its three fixed-target experiments: (i) MAGIX, (ii) P2, and (iii) DarkMESA. MAGIX exploits MESA's energy-recovery operation to deliver very high beam currents onto a windowless gas-jet target, surrounded by two high-resolution magnetic spectrometers. This unique combination opens up competitive measurements of the proton radius, searches for dark-sector particles, and nuclear-astrophysics reaction studies. The P2 experiment runs in MESA's external-beam mode and measures the parity-violating spin asymmetry, yielding the electroweak mixing angle at low momentum transfer. Comparison with the Standard Model prediction probes new physics at scales up to 50 TeV, and additionally constrains the neutron skin of nuclei. Finally, the DarkMESA beam-dump experiment, installed downstream of P2, searches for hypothetical light dark-matter particles.