No Arabic abstract
Recent discovery of a Higgs boson boosted interest in a low-energy medium-luminosity Muon Collider as a Higgs Factory (HF). A preliminary design of the HF storage ring (SR) is based on cos-theta Nb3Sn superconducting (SC) magnets with the coil inner diameter ranging from 50 cm in the interaction region to 16 cm in the arc. The coil cross-sections were chosen based on the operation margin, field quality and quench protection considerations to provide an adequate space for the beam pipe, helium channel and inner absorber (liner). With the 62.5-GeV muon energy and 2 x 10^12 muons per bunch, the electrons from muon decays deposit about 300 kW in the SC magnets, or unprecedented 1 kW/m dynamic heat load, which corresponds to a multi-MW room temperature equivalent. Based on the detailed MARS15 model built and intense simulations, a sophisticated protection system was designed for the entire SR to bring the peak power density in the SC coils safely below the quench limit and reduce the dynamic heat load to the cold mass by a factor of 100. The system consists of tight tungsten masks in the magnet interconnect regions and elliptical tungsten liners optimized for each magnet.
Low-energy medium-luminosity Muon Collider (MC) is being studied as a possible Higgs Factory (HF). Electrons from muon decays will deposit more than 300 kW in superconducting magnets of the HF collider ring. This imposes significant challenges to superconducting (SC) magnets used in the MC storage ring (SR) and interaction regions (IR). The magnet designs are proposed which provide high operating gradient and magnetic field in a large aperture to accommodate the large size of muon beams due to low b{eta}* as well as the cooling system to intercept the large heat deposition from the showers induced by decay electrons. Specific distribution of heat deposition in the lattice elements MC SR requires large aperture magnets to accommodate thick high-Z absorbers to protect the SC coils. Based on the developed MARS15 model and intense simulations, a sophisticated radiation protection system was designed for the collider SR and IR to bring the peak power density in the superconducting coils below the quench limit and reduce the dynamic heat deposition in the cold mass by a factor of 100. The system consists of tight tungsten masks in the magnet interconnect regions and elliptical tungsten liners in magnet aperture optimized for each magnet. It also reduces the background particle fluxes in the collider detector.
Because muons connect directly to a standard-model Higgs particle in s-channel production, a muon collider would be an ideal device for precision measurement of the mass and width of a Higgs-like particle, and for further exploration of its production and decay properties. Parameters of a high-precision muon collider are presented and the necessary components and performance are described. An important advantage of the muon collider approach is that the spin precession of the muons will enable energy measurements at extremely high accuracy (dE/E to 10-6 or better). The collider could be a first step toward a high-luminosity multi-TeV lepton collider, and extensions toward a higher-energy higher-luminosity device are also discussed.
We propose the construction of, and describe in detail, a compact Muon Collider s-channel Higgs Factory.
We propose the construction of a compact Muon Collider Higgs Factory. Such a machine can produce up to sim 14,000 at 8times 10^{31} cm^-2 sec^-1 clean Higgs events per year, enabling the most precise possible measurement of the mass, width and Higgs-Yukawa coupling constants.
A neutrino factory or muon collider requires the capture and cooling of a large number of muons. Scenarios for capture, bunching, phase-energy rotation and initial cooling of {mu}s produced from a proton source target have been developed, initially for neutrino factory scenarios. They require a drift section from the target, a bunching section and a {phi}-{delta}E rotation section leading into the cooling channel. Important concerns are rf limitations within the focusing magnetic fields and large losses in the transport. The currently preferred cooling channel design is an HFOFO Snake configuration that cools both {mu}+ and {mu}- transversely and longitudinally. The status of the design is presented and variations are discussed.