The physics capabilities of μ[sup +]μ[sup −] colliders

Abstract

Abstract. We summarize the potential of muon colliders to probe fundamental physics. W + W − ,tt, and Zh threshold measurements could determine masses to precisions ∆M W = 6 MeV, ∆m t = 70 MeV, and ∆m h = 45 MeV, to test electroweak radiative corrections. With s-channel Higgs production, unique to a muon collider, the Higgs mass could be pinpointed (∆m h < 1 MeV) and its width measured. The other Higgs bosons of supersymmetry can be produced and studied by three methods. If instead the W W sector turns out to be strongly interacting, a 4 TeV muon collider is ideally suited to its study. I INTRODUCTIONIn this report we address the exciting physics that could be accomplished at muon colliders in the context of the central physics issue of our time: how is the electroweak symmetry broken, weakly or strongly? Higgs bosons and a low energy supersymmetry (SUSY) are the particles of interest in the weakly broken scenario and new resonances at the TeV scale of a new strong interaction dynamics are the alternatives.Muon colliders would have decided advantages over other machines in providing (i) sharp beam energy for precision measurements of masses, widths and couplings of the Higgs, W , t and supersymmetry particles, and (ii) high energy / high luminosity for production of high mass particles and studies of a strongly interacting electroweak sector (SEWS).In order to be able to do interesting physics at a muon collider, the minimum luminosity requirement is * ) Talk presented by V.

Minimal supersymmetric standard model Higgs bosons in the intense-coupling regime

“…Present estimates for yearly integrated luminosities are L = 0.1, 0.22, 1 fb −1 for beam energy resolutions of R = 0.003%, 0.01%, 0.1%, respectively [66].…”

“…[65][66][67]. The main advantages of a muon collider, compared to an electron-positron machine, are due to the fact that the muon has a much larger mass than the electron, which means that: (i) The couplings of Higgs bosons to µ + µ − pairs are much larger than the couplings to e + e − pairs, yielding significantly larger rates for s-channel Higgs boson production at a muon collider [the production rate is negligible in e + e − collisions].…”

Electroweak symmetry breaking and higgs physics

“…After opening up the real and virtual gauge-boson channels, the state rapidly becomes wider, reaching a width of ∼ 1 GeV at the ZZ threshold. The width cannot be measured directly in the intermediate mass region at the LHC or e + e − colliders; however, it could be measured directly at muon colliders [35]. Above a mass of ∼ 250 GeV, the state becomes wide enough to be resolved experimentally in general.…”

“…The direct measurement of the width in the intermediate mass range will be possible at muon colliders in which Higgs bosons can be generated as s-channel resonances: µ + µ − → H → ff, V V . The energy resolution of the muon beams is expected to be so high that the Breit-Wigner excitation curve can be reconstructed [35].…”

Higgs boson physics in the s-channel at μ+μ− colliders

“…There are many other motivations for building a µ + µ − collider, especially one with √ s > ∼ 2 TeV, based on other types of new physics that could be probed. The physics motivations for a high-energy µ + µ − collider will be treated elsewhere [34].…”