muCool: muon cooling for high-brightness μ+ beams

Abstract

A number of experiments with muons are limited by the poor phase\nspace quality of the muon beams currently available. The muCool project\naims at developing a phase-space cooling method to transform a surface\n\\mu^+μ+\nbeam with 4 MeV energy and 1 cm size into a slow muon beam with eV\nenergy and 1 mm size. In this process the phase space is reduced by a\nfactor of 10^{9}-10^{10}109−1010\nwith efficiencies of 2\\cdot 10^{-5}-2\\cdot 10^{-4}2⋅10−5−2⋅10−4.\nThe beam is then re-accelerated to keV-MeV energies. Such a beam opens\nup new avenues for research in fundamental particle physics with muons\nand muonium atoms as well as in the field of\n\\muμSR\nspectroscopy.