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Cool Muon Colliders

This presentation discusses the concept, history, and physics of cool muon colliders, including their potential for Higgs and neutrino physics. It also explores the challenges of cooling muons and different cooling methods.

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Cool Muon Colliders

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  1. Cool Muon Colliders Studies at Columbia University & Nevis Labs Raphael Galea Allen Caldwell Stefan Schlenstedt (DESY/Zeuten) Halina Abramowitz(Tel Aviv University) Summer Students: Christos Georgiou Daniel Greenwald Yujin Ning Inna Shpiro Will Serber

  2. Cool Muon Colliders: Caltech October 9, 2001 Outline • Muon Colliders Motivation • History • Physics • Higgs, neutrino physics, new & old physics • Cooling obstacle • Ionization cooling • Frictional cooling

  3. Cool Muon Colliders: Caltech October 9, 2001 History • Concept first proposed to Budker & Skrinsky in 60’s and early 70’s • Ionization cooling developed by Skrinsky & Parkhomchuk in 1981 • Furthered by Neuffer & Palmer resulting in formation of Muon Collider collaboration in 1995

  4. Cool Muon Colliders: Caltech October 9, 2001 The Future • Lepton Collider clean but limited in energy by synchrotron radiationa 1/m^4 • Hardron Collider higher energy Mp~2000xMe • 1/3-1/10 energy taking part in collision • Difficult to separate the underlying event • Muon Collider • Not limited by synchrotron radiation Mm~200xMe • Easily scaleable • Compact machines

  5. Cool Muon Colliders: Caltech October 9, 2001

  6. Cool Muon Colliders: Caltech October 9, 2001 Livingston Curve

  7. Cool Muon Colliders: Caltech October 9, 2001 Muon Collider in Perspective

  8. Cool Muon Colliders: Caltech October 9, 2001 Physics Motivation • m+m- couple directly to Higgs • S channel • Muons can be polarized (20% polarization will be achievable) • High beam resolution • If proven technology machine scalable • High mass resonances,technicolour, SUSY… • Cool muons can be used as a source of n’s HIGGS FACTORY

  9. Cool Muon Colliders: Caltech October 9, 2001 Higgs Factory

  10. Cool Muon Colliders: Caltech October 9, 2001 Higgs Properties • Scan 0.0015fb-1/point • 1 year of running at L=1.5x1031cm-2 s-1 • (0.15fb-1)/year to measure Higgs mass to 1-2 MeV

  11. Cool Muon Colliders: Caltech October 9, 2001 Light Higgs • Gh=2-3 MeV • Gh=2-3 MeV for tanb<2 • Gh=2-500 MeV for tanb~50

  12. Cool Muon Colliders: Caltech October 9, 2001 Resolving Mass Degeneracies

  13. Cool Muon Colliders: Caltech October 9, 2001 No Higgs @ LHC?? With 10fb-1 of lumi devoted to threshold scan: m+m- W+W- Dm(W)=20MeV m+m- t+t- Dm(t)=200MeV m+m- Zh Dm(h)=140MeV

  14. Cool Muon Colliders: Caltech October 9, 2001 Supersymmetry • 50fb-1 can lead to DM(c+)=35,45MeV for • M(c+)=100 MeV & M(v)=500,300 GeV • Heavy SUSY scalar pair production is p-wave suppresseM=1TeV requires collider of 3-4TeV CMS

  15. Cool Muon Colliders: Caltech October 9, 2001 Cooling Motivation • p produced by intense p beam on target • p captured by strong focusing field • p to m • Resulting muons occupy large & diffuse phase space

  16. Cool Muon Colliders: Caltech October 9, 2001 Ionization Cooling • Transverse Cooling • Muons lose energy by dE/dx & replaced longitudinally by RF • High field solenoids • low Z absorbers

  17. Cool Muon Colliders: Caltech October 9, 2001 Longitudinal Cooling • Ionization cooling using a wedge absorber + dispersion • Exchange emittance between transverse & longitudinal direction

  18. Cool Muon Colliders: Caltech October 9, 2001 Frictional Cooling • Bring muons to a kinetic energy (T) range where dE/dx increases with T • Constant E-field applied to muons resulting in equilibrium energy

  19. Cool Muon Colliders: Caltech October 9, 2001 Problems/Comments: • large dE/dx @ low kinetic energy • low average density • Apply to get below the dE/dx peak • m+has the problem of Muonium formation • s(Mm) dominates over e-stripping s in all gases except He • m-has the problem of Atomic capture • s calculated up to 80 eV not measured below ~1KeV • Cool m’s extracted from gas cell T=1ms so a scheme for reacceleration must be developed

  20. Cool Muon Colliders: Caltech October 9, 2001 Basic Design

  21. Cool Muon Colliders: Caltech October 9, 2001 Muon Motion in Cooling Cell

  22. Cool Muon Colliders: Caltech October 9, 2001 Target Optimization • Want low energy muons hence need to optimize pion production accordingly for: • Proton Driver Energy • Target Material • Target Dimensions • Target Orientation Peripheral Central

  23. Cool Muon Colliders: Caltech October 9, 2001 Magnet Capture Peripheral Central p p+,m+ p+ p- m+ m- p p-,m- • +ve & -ve in same channel • Separate charges at source

  24. Cool Muon Colliders: Caltech October 9, 2001 Phase Rotation • Apply simple E-field form : • Optimize muon yield as a function of t1,t2 & Length of the phase rotation region Emax t1 t2

  25. Cool Muon Colliders: Caltech October 9, 2001

  26. Cool Muon Colliders: Caltech October 9, 2001 Multiple Scattering • To date simulations only considered continuous dE/dx • May turn out that component of E-fieldparallel to B-field needed • Technically difficult because of large angle scatters at low energies

  27. Cool Muon Colliders: Caltech October 9, 2001 PSI Experiment • Experiment study Lamb Shift in Muonic Atoms • Muon Spectrum 10-40KeV • 5T Magnet with D=20cm bore

  28. Cool Muon Colliders: Caltech October 9, 2001 Nevis Setup

  29. Vary E-field, density & length of gas cell Simulation with no Multiple Scattering E-field parallel to B-field so muons do not stop Cool Muon Colliders: Caltech October 9, 2001 Simulation @ Nevis

  30. Cool Muon Colliders: Caltech October 9, 2001

  31. Cool Muon Colliders: Caltech October 9, 2001

  32. Cool Muon Colliders: Caltech October 9, 2001 Goals of Experiment • Measure X-ray released from capture in Gas Atom • Check understanding of energy loss, multiple scattering • Measure m- capture cross section at low energies in He & H2

  33. Cool Muon Colliders: Caltech October 9, 2001 Nevis lab: • Multipurpose Vacuum Chamber • Fast Logic Readout • MCP Detector • X-ray MWPC development underway

  34. Cool Muon Colliders: Caltech October 9, 2001 MWPC X-ray Detector • 4 channel prototype • Possible extension to tracker – track decay e- from captured m-

  35. Cool Muon Colliders: Caltech October 9, 2001 Summary • Muon Colliders promise a bright future for HEP • Physics Factory, Higgs, n’s, s-channel resonances • Major hurdle is cooling but efforts are going forward with a plan to demonstrate emittance exchange • Exciting alternative concept for muon cooling • Frictional Cooling • Possibility to cool both signs at once • Experiment to measure m- capture cross section planned…..STAY TUNED

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