A ring lattice for a 2-TeV muon collider

Abstract

A 2 TeV on 2 TeV muon collider has been proposed with a design luminosity of 10/sup 35/ cm/sup -2/ s/sup -1/. The ring has a circumference of about 8 km, and the muon lifetime at 2 TeV corresponds to approximately 1000 turns before the beam luminosity degrades substantially. The cooling process produces a round beam with a normalized emittance of 50/spl times/10/sup -5/ mrad and 2/spl times/10/sup 12/ muons per bunch. The beam's large emittance requires that /spl beta/* at the interaction point (IP) must be only 3/spl times/10/sup -3/ m, in order to reach the design luminosity. Due to the hourglass effect, a very short bunch length equal to /spl beta/* must be maintained to reach the design luminosity. To prevent the bunch from spreading in time, the momentum compaction factor /spl alpha/ must be 10/sup -5/, or less; that is, the ring must be nearly isochronous. The small value of /spl beta/* leads to very large peak beta values in the final-focus quadrupoles, and unprecedented chromaticities. Correction of the large chromaticities makes for a highly nonlinear interaction region (IR). This IR, combined with the isochronicity condition, makes design of a muon collider lattice very challenging. The lattice presented here builds on a base ring design described in a feasibility report, and, more recently, in several muon-collider workshop proceedings.