MESA - Mainz Energy-Recovering Superconducting Accelerator
At MESA, we explore the physics opportunities offered by using the recently established Energy-Recovery-Linac (ERL) accelerator technology which enables very high electron-beam luminosities on internal targets at low energies. MESA will be the first accelerator to investigate multiturn energy recovery in a superconducting environment. The machine will therefore serve as a test-bed for world-scale facilities such as the LHeC .
MESA not only is a pioneering project for ERL applications, it will also pave the route for highly visible experiments in particle physics:
- The possible existence of new light vector bosons that couple to the dark sector (“dark photons”) has received widespread attention, prompting many leading laboratories worldwide to include searches for these particles into their long-term research plans. At Mainz JGU, physicists have already spearheaded attempts to discover hints of dark photons in ongoing electron-nucleus scattering experiments  and the construction of the MESA accelerator will enable us to boost our programme to search for dark photons.
- The ERL mode will be exploited in searches for new light gauge bosons in the region of parameter space which could explain the observed anomalous magnetic moment of the muon - one of the most promising hunting grounds for a discovery experiment.
- MESA can also be used in extracted beam (EB) mode where extreme luminosities of >1039 cm-2s-1 can be achieved. Operated in EB-mode, with its highly spin-polarized beam, MESA will therefore be a key facility for a new generation of precision experiments to measure fundamental parameters such as the electroweak mixing angle.
 J.L. Abelleira Fernandez et al., A Large Hadron Electron Collider at CERN: Report on the Physics and Design Concepts for Machine and Detector, J. Phys. G39 (2012) 075001.
 H. Merkel et al., Search for Light Gauge Bosons of the Dark Sector at the Mainz Microtron, Phys. Rev. Lett. 106, 251802 (2011).