1 / 26

Physics at a Future Muon Collider

Physics at a Future Muon Collider. Amit Klier University of California, Riverside WIN’05 – Delphi, Greece – June 2005. OUTLINE. Why muon colliders? Advantages Problems Some physics Light Higgs Factory Heavy Higgs Toward a muon collider Recent advances in 6-D Cooling R&D. Why Muons?.

helene
Download Presentation

Physics at a Future Muon Collider

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Physics at a FutureMuon Collider Amit Klier University of California, Riverside WIN’05 – Delphi, Greece – June 2005 A. Klier - Muon Collider Physics

  2. OUTLINE • Why muon colliders? • Advantages • Problems • Some physics • Light Higgs Factory • Heavy Higgs • Toward a muon collider • Recent advances in 6-D Cooling R&D A. Klier - Muon Collider Physics

  3. Why Muons? • As fundamental as electrons… • Unlike p, p, all the collision energy is useful • …and 200 times as heavy Sync. radiation energy loss is 2 billion times less: • Compact storage rings up to a few TeV • Very good energy resolution Coupling to the Higgs boson is 40,000 times greater: • Produce Higgs Bosons via the s-channel A. Klier - Muon Collider Physics

  4. Muon Colliders, Other Machines A. Klier - Muon Collider Physics

  5. The Problem with Muons • They DECAY: muon lifetime = 2.2 ms Everything has to be fast, specifically: • Cooling (ionization) • Acceleration (RLA, FFAG) • Muon Collider detectors need shielding against g’s from decay electrons • Decay neutrinos can be harmful at Emm≳4 TeV (they can be useful for a Neutrino Factory, but that’s for another talk) A. Klier - Muon Collider Physics

  6. Some Physics A. Klier - Muon Collider Physics

  7. Light Higgs Boson • Precision EW data seem to favor light SM Higgs Boson • So does SUSY (from theory) A. Klier - Muon Collider Physics

  8. SM (or SM-like) Higgs Factory • Higgs Boson width – few MeV for mhSM<160 GeV • Fine scan for DE≲ G hSM Use spin precession for in situ energy determination to ~1 ppm • Luminosity is compromised by resolution, e.g. R=0.003% Lyear~ 0.1 fb-1 R=0.01% Lyear~ 0.22 fb-1 R=0.1% Lyear~ 1.0 fb-1 ( R≡2DE/E ) A. Klier - Muon Collider Physics

  9. Precision Measurements • For a SM-like ~110-GeV Higgs Boson, a muon collider Higgs Factory can measure the mass to an uncertainty of ~10-6 with L=0.2 fb-1 (compared to ~10-4 at a 500 GeV, 500 fb-1 LC and ~10-3 at the LHC) • Only in the s-channel Gh can be measured directly (otherwise need accurate WW* rate measurement, difficult at mh<120 GeV) • Precise measurement of the cross section of m+m-h0bb– independent of mb A. Klier - Muon Collider Physics

  10. Heavy Higgs Bosons • SUSY H0 and A0 may be observed at the LHC • Light h0 indicate high tanb, which implies greater H0-A0mass degeneracy • Muon g-2 results also favor high tanb values (≳8), with similar consequences • An “intermediate energy” (few hundred GeV) muon collider can be used to scan the the heavy Higgs mass range & separate the two A. Klier - Muon Collider Physics

  11. Separating the Heavy Higgses A. Klier - Muon Collider Physics

  12. Another Scenario • For some values of tanb (~8-10) and mA (≳250 GeV) LHC/LC may not be able to observe H0 or A0 • A muon collider may be needed to discover the heavy Higgs in this region A. Klier - Muon Collider Physics

  13. CP Violation in the Higgs Sector • Polarized muon beams can be used to measure CP violation in the Higgs sector A. Klier - Muon Collider Physics

  14. R&D Advances A. Klier - Muon Collider Physics

  15. Toward a Muon Collider • The physics part of this talk is mostly based on Snowmass 2001 (and earlier) results. That’s “old news” • Muon Collaboration attention has shifted to the (seemingly more feasible, and probably as important) neutrino factory • This shouldn’t have affected the Muon Collider R&D effort… • Indeed, impressive advances were made, especially in simulating 6-D cooling A. Klier - Muon Collider Physics

  16. How To Build a Muon Collider + p ±± - proton linac proton driver (a few MW) target pion decay muon cooling muon acceleration (up to 0.1 - 3 TeV) storage ring detector A. Klier - Muon Collider Physics

  17. How Much Cooling is Needed Light Higgs Factory Beam reduction of about 100 needed in each transverse and in the longitudinal direction (~106 6-D cooling) compared with muons from pion decay A. Klier - Muon Collider Physics

  18. 6-D Cooling absorber absorber • Ionization cooling: Fast, but cools only in transverse directions (sufficient for n factory) • 6-D cooling via emittance exchange: Repeated cooling/ emittance exchange cools m beam in all six phase-space dimensions RF RF  large angular spread small angular spread A. Klier - Muon Collider Physics

  19. Ring Coolers • First suggested by V.Balbekov in 2001 • 6-D cooling – about 50 However: • Problems trying to introduce realistic magnetic fields • Injection/extraction very difficult and affects performance badly A. Klier - Muon Collider Physics

  20. The RFOFO Ring • Suggested by R.Palmer in 2002 • 6-D cooling ~300 • Simulations work with realistic magnetic field • Injection/extraction still a problem, but performance is less affected (still cools by about 200) A. Klier - Muon Collider Physics

  21. Gas-Filled Cooling Ring • The idea: use the dipole volume itself as a “wedge absorber” by filling it with high-pressure H2 gas • Small Dipole Ring – suggested by A.Garren, H.Kirk in 2004 • Can be used to demonstrate 6D cooling experimentally: moderate performance, but low cost (no SC…) 1.6 m A. Klier - Muon Collider Physics

  22. Further Cooling – Lithium Lens • Recently simulated transverse cooling down to ~0.3 mm • But longitudinal emittance blows up • Latest development use bent Lithium Lenses (“ Li ring”) A. Klier - Muon Collider Physics

  23. Helical Cooling Channel • Suggested by Y.Derbenev/Muons Inc. • High-pressure-H2-filled helical dipole & RF cavities in a solenoid • Simulated cooling: 300 • Advantage: no need for injection/kicker • Challenges: high dipole fields, rather complicated A. Klier - Muon Collider Physics

  24. Parametric Resonance Cooling • Suggested by Y.Derbenev & Muons Inc. • Potential cooling10 after the HCC/ Ring Cooler A. Klier - Muon Collider Physics

  25. Reversed Emittance Exchange • For TeV-scale muon colliders, longitudinal cooling is sufficient, but more transverse cooling is needed • Reverse the emittance exchange process A. Klier - Muon Collider Physics

  26. Conclusions • Muon colliders can contribute to Higgs physics in unique ways, complement LHC/LC • Being compact, muon colliders may eventually cost less than the “conventional” ones (LHC/LC), but are extremely challenging • A lot of progress in 6-D cooling simulations • Greater effort is needed to put everything together, demonstrate 6-D cooling in real life A. Klier - Muon Collider Physics

More Related