Final Cooling with Thick Wedges for a Muon Collider

A future 10 TeV muon collider offers enormous potential to directly search for new physics and perform percent-level precision measurements of Standard Model properties. An important component of such a collider is cooling, in which the emittance of muons produced in collisions is reduced to produce a beam suitable for use in a collider. In the last stage of this process, called final 4D cooling, emittance in the transverse axes is reduced while emittance in the longitudinal axis is allowed to grow. In previous studies, final 4D cooling was achieved using absorbers within very high field solenoids to cool low-momentum muons. Simulations of these systems with realistic magnets did not reach the desired cooling design goals. In this study, we develop and simulate a different design for the final 4D cooling channel, which is based on single thick wedges. This design has the potential to achieve cooling goals with existing magnet technology. We optimized the design parameters of the cooling channel and achieve cooling in both transverse axes by a factor of ~3.5. These channels achieve a lower transverse and longitudinal emittance than the best design previously published. This work demonstrates the viability of the wedge-based cooling channel and motivates further study on alternative designs to achieve final cooling.