In the next decade the Fermilab Muon Campus will provide the most intense pulsed muon beams, which are among the cleanest probes when searching for new phenomena beyond the Standard Model (BSM) of fundamental interactions. The goal of the Muon (g-2) experiment at FNAL is to solve the puzzle originated by the existing 3 standard deviations discrepancy between the value of aμ predicted in the Standard Model (SM) and the measurement performed by the E821 Collaboration at Brookhaven. Muon (g-2) aims for a precision of 0.14 parts per million (ppm) on aμ, which corresponds to a factor of 4 improvement with respect to the BNL measurement. This accuracy will provide more than 5 standard deviations discrepancy from the existing theoretical prediction if the aμ central value remains unchanged. Mu2e will search for the Charged Lepton Flavour Violating (CLFV) neutrinoless, coherent muon conversion to an electron in the Coulomb field of a nucleus, with four orders of magnitude improved sensitivity with respect to previous experiments. The observation of lepton flavour violation in the neutral lepton sector, named “neutrino oscillations”, was accommodated by an ad hoc modification of the SM, but no mechanism within the model allows for a measurable rate of CLFV. The observation of CLFV would be an unambiguous evidence of new physics. An international program is currently underway to improve the sensitivity reach using muons probes, which are free of the complications of hadronic uncertainties. In Europe the upgrade of the MEG experiment at Paul Scherrer Institute (PSI) has the goal to search for the muon decay in flight to an electron and a photon. There is also the new proposal of the Mu3e experiment at PSI, whose goal is to search for the muon decay to ee+ e. Mu2e at FNAL and COMET at JPARC will search for the muon coherent conversion to an electron in the Coulomb field of a nucleus. These experiments complement and extend the current MEG and Mu3e searches. CLFV phenomena probe new physics at a mass scale significantly beyond LHC direct searches and may provide the first evidence of new physics. Furthermore, many models predicting new physics at the mass scale accessible at LHC, also predict CLFV processes at rates within Mu2e reach. Mu2e will thus provide complementary information in case of a discovery at LHC. In the Muon (g-2) and Mu2e experiments the NEWS researchers have leading roles in the detectors development and in the beamline infrastructure. They have designed and will contribute to the construction of the Mu2e superconducting solenoid transporting the high intensity muon beam from the production to the stopping target, where muons decay or possibly convert. NEWS researchers will participate in the international effort for the development of the Nb 3 Sn technology to produce 16 T Nb 3 Sn solenoid and bending magnets, which are fundamental for future particle collider projects. In collaboration with FNAL and CALTECH, NEWS researchers will also develop superconductivitybased detectors, bolometers and microcalorimeters, for applications in cosmology, astrophysics and particle physics. These detectors are well suited for the multimessenger approach, given the wide range of detectable radiation, from millimeter waves, to optical photons, X-rays, gamma rays, nuclear decays and energetic particles. NEWS focus is on the development of Transition Edge Sensors (TES), which offer unprecedented detecting capabilities for LSPE and future experiments.
Fermi National Accelerator Laboratory
Japan Proton Accelerator Research Complex (JPARC)