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

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea Outline Muon Colliders Motivation –History Physics –Higgs, neutrino physics, new & old physics Cooling obstacle –Ionization cooling –Frictional cooling

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea 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

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea The Future Lepton ColliderLepton Collider clean but limited in energy by synchrotron radiation  1/m^4 Hardron ColliderHardron Collider higher energy Mp~2000xMe –1/3-1/10 energy taking part in collision –Difficult to separate the underlying event Muon ColliderMuon Collider –Not limited by synchrotron radiation M  ~200xMe –Easily scaleable –Compact machines

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea Livingston Curve

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea Muon Collider in Perspective

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea Physics Motivation  +  - 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 ’s HIGGS FACTORY

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea Higgs Factory

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea Higgs Properties Scan fb -1 /point 1 year of running at L =1.5x10 31 cm -2 s -1 (0.15fb -1 )/year to measure Higgs mass to 1-2 MeV

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea Light Higgs  h=2-3 MeV  h=2-3 MeV for tan  <2  h=2-500 MeV for tan  ~50

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea Resolving Mass Degeneracies

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea No LHC?? With 10fb-1 of lumi devoted to threshold scan:  +  - W+W-  m(W)=20MeV  +  - t+t-  m(t)=200MeV  +  - Zh  m(h)=140MeV  +  - Zh  m(h)=140MeV

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea Supersymmetry M=1TeV requires collider of 3-4TeV CMS Heavy SUSY scalar pair production is p-wave suppresse M=1TeV requires collider of 3-4TeV CMS 50fb -1 can lead to  M(  MeV for M(  eV & M(v)=500,300 GeV

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea Cooling Motivation   produced by intense p beam on target 2.  captured by strong focusing field 3.  to  Resulting muons occupy large & diffuse phase space

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea Ionization Cooling Transverse Cooling Muons lose energy by dE/dx & replaced longitudinally by RF High field solenoids High field solenoids low Z absorbers low Z absorbers

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea Longitudinal Cooling Ionization cooling using a wedge absorber + dispersion Exchange emittance between transverse & longitudinal direction

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea 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

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea Problems/Comments: large low kinetic energy low average density Apply to get below the dE/dx peak  has the problem of Muonium formation  dominates over e-stripping  in all gases except He  has the problem of Atomic capture  calculated up to 80 eV not measured below ~1KeV Cool  ’s extracted from gas cell T=1  s so a scheme for reacceleration must be developed

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea Basic Design

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea Muon Motion in Cooling Cell

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea Target Optimization Want low energy muons hence need to optimize pion production accordingly for: –Proton Driver Energy –Target Material –Target Dimensions –Target Orientation PeripheralCentral

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea Magnet Capture PeripheralCentral    +ve & -ve in same channel +ve & -ve in same channel Separate charges at sourceSeparate charges at source p p

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea Phase Rotation Apply simple E-field form : Optimize muon yield as a function of t1,t2 & Length of the phase rotation region t1t2 Emax

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea Multiple Scattering To date simulations only considered continuous dE/dx May turn out that component of E-field parallel to B-field needed Technically difficult because of large angle scatters at low energies

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea PSI Experiment Experiment study Lamb Shift in Muonic Atoms Muon Spectrum 10-40KeV 5T Magnet with D=20cm bore

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea Nevis Setup

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea Nevis 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 Columbia University/Nevis Labs Raphael Galea

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea Goals of Experiment Measure X-ray released from capture in Gas Atom Check understanding of energy loss, multiple scattering Measure  - capture cross section at low energies in He & H2

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea Nevis lab: Multipurpose Vacuum Chamber Fast Logic Readout MCP Detector X-ray MWPC development underway

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea MWPC X-ray Detector 4 channel prototype Possible extension to tracker – track decay e- from captured  -

Cool Muon Colliders: Caltech October 9, 2001 Columbia University/Nevis Labs Raphael Galea Summary Muon Colliders promise a bright future for HEP –Physics Factory, Higgs, ’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  - capture cross section planned…..STAY TUNED