Laser Cooling of Tev Muons * Fermilab-conf-00/162

Muon colliders are a possible future tool for the exploration of physics at the TeV scale and beyond. The current status of the developent of the muon collider concept is described in Ref. [1], which includes a description of a 3 TeV center-ofmass (COM) machine. One of the major challenges to realizing a highluminosity muon collider is to cool the diffuse bunches of muons produced in pion decays. Much effort is being put into the problem of quickly cooling these bunches at the front-end of a muoncollider and maintaining the low emittance while bunches are being accelerated and brought into collision. For the 3 TeV COM machine, the problems of neutrino radiation [2] and power consumption are already becoming prohibitive. Additional cooling of the bunches after acceleration would mitigate these problems by allowing a given luminosity to be attained with fewer stored muons and a lower repitition rate, and allow consideration of even higher energy muon colliders. For example, the tunnels and high-field magnets being discussed for future hadron colliders [3] could ultimately be used for a 100 TeV-scale muon collider. Postacceleration cooling would also reduce detector backgrounds from muon decay. The possibility of using Compton scattering for cooling of electron bunches for γγ colliders has been previously considered [4]. The luminosity for ee collisions is already limited by beamstrahlung effects, but additional cooling may greatly improve the γγ luminosity.