No Arabic abstract
We show that a muon collider is ideally suited for the study of heavy H/A scalars, cousins of the Higgs boson found in two-Higgs doublet models and required in supersymmetric models. The key aspects of H/A are: (1) they are narrow, yet have a width-to-mass ratio far larger than the expected muon collider beam-energy resolution, and (2) the larger muon Yukawa allows efficient s-channel production. We study in detail a representative Natural Supersymmetry model which has a 1.5 Tev H/A with $m_H$- $m_A$ = 10 Gev. The large event rates at resonant peak allow the determination of the individual H and A resonance parameters (including CP) and the decays into electroweakinos provides a wealth of information unavailable to any other present or planned collider.
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.
The LHCb measurements of the $mu / e$ ratio in $B to K ell ell$ decays $(R_{K^{}})$ indicate a deficit with respect to the Standard Model prediction, supporting earlier hints of lepton universality violation observed in the $R_{K^{(*)}}$ ratio. Possible explanations of these $B$-physics anomalies include heavy $Z$ bosons or leptoquarks mediating $b to s mu^+ mu^- $. We note that a muon collider can directly measure this process via $mu^+ mu^- to b bar s$ and can shed light on the lepton non-universality scenario. Investigating currently discussed center-of-mass energies $sqrt{s} = 3$, 6 and 10 TeV, we show that the parameter space of $Z$ and $S_3$ leptoquark solutions to the $R_{K^{(*)}}$ anomalies can be mostly covered. Effective operators explaining the anomalies can be probed with the muon collider setup $sqrt{s} = 6~{rm TeV}$ and integrated luminosity $L = 4~{rm ab^{-1}}$.
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.