Transcript Low Energy Muon Cooling : Frictional Cooling

Cool Muon Colliders
Studies at Columbia University & Nevis Labs
Raphael Galea
Allen Caldwell
Stefan Schlenstedt (DESY/Zeuten)
Halina Abramowitz(Tel Aviv University)
Summer Students:
http://www.nevis.columbia.edu/~galea/mucos
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
http://www.nevis.columbia.edu/~galea/mucos
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
http://www.nevis.columbia.edu/~galea/mucos
Cool Muon Colliders:
Caltech October 9, 2001
Columbia University/Nevis Labs
Raphael Galea
The Future
• Lepton Collider clean but limited in energy by
synchrotron radiation a 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
http://www.nevis.columbia.edu/~galea/mucos
Cool Muon Colliders:
Caltech October 9, 2001
Columbia University/Nevis Labs
Raphael Galea
http://www.nevis.columbia.edu/~galea/mucos
Cool Muon Colliders:
Caltech October 9, 2001
Columbia University/Nevis Labs
Raphael Galea
Livingston Curve
http://www.nevis.columbia.edu/~galea/mucos
Cool Muon Colliders:
Caltech October 9, 2001
Columbia University/Nevis Labs
Raphael Galea
Muon Collider in Perspective
http://www.nevis.columbia.edu/~galea/mucos
Cool Muon Colliders:
Caltech October 9, 2001
Columbia University/Nevis Labs
Raphael Galea
Physics Motivation
• m+m- couple directly to Higgs
– S channel
HIGGS FACTORY
• 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
http://www.nevis.columbia.edu/~galea/mucos
Cool Muon Colliders:
Caltech October 9, 2001
Columbia University/Nevis Labs
Raphael Galea
Higgs Factory
http://www.nevis.columbia.edu/~galea/mucos
Cool Muon Colliders:
Caltech October 9, 2001
Columbia University/Nevis Labs
Raphael Galea
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
http://www.nevis.columbia.edu/~galea/mucos
Cool Muon Colliders:
Caltech October 9, 2001
Columbia University/Nevis Labs
Raphael Galea
Light Higgs
 Gh=2-3 MeV
 Gh=2-3 MeV for
tanb<2
 Gh=2-500 MeV for
tanb~50
http://www.nevis.columbia.edu/~galea/mucos
Cool Muon Colliders:
Caltech October 9, 2001
Columbia University/Nevis Labs
Raphael Galea
Resolving Mass Degeneracies
http://www.nevis.columbia.edu/~galea/mucos
Cool Muon Colliders:
Caltech October 9, 2001
Columbia University/Nevis Labs
Raphael Galea
No Higgs @ LHC??
With 10fb-1 of lumi devoted to threshold scan:
m+m- W+WDm(W)=20MeV
m+m- t+tDm(t)=200MeV
m+m- Zh
Dm(h)=140MeV
http://www.nevis.columbia.edu/~galea/mucos
Cool Muon Colliders:
Caltech October 9, 2001
Columbia University/Nevis Labs
Raphael Galea
Supersymmetry
• Heavy
•50fb-1 can lead to DM(c+)=35,45 MeV for
•M(c+)=100 MeV & M(v)=500,300 GeV
SUSY
scalar pair
production
is p-wave
suppresse
M=1TeV
requires
collider of
3-4TeV
CMS
http://www.nevis.columbia.edu/~galea/mucos
Cool Muon Colliders:
Caltech October 9, 2001
Columbia University/Nevis Labs
Raphael Galea
Cooling Motivation
1.
2.
3.
•
http://www.nevis.columbia.edu/~galea/mucos
p produced by
intense p beam
on target
p captured by
strong focusing
field
p to m
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
• low Z absorbers
http://www.nevis.columbia.edu/~galea/mucos
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
http://www.nevis.columbia.edu/~galea/mucos
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
http://www.nevis.columbia.edu/~galea/mucos
Cool Muon Colliders:
Caltech October 9, 2001
Columbia University/Nevis Labs
Raphael Galea
Problems/Comments:
• large dE/dx @ low kinetic energy
• low average density


• Apply E  B 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
http://www.nevis.columbia.edu/~galea/mucos
Cool Muon Colliders:
Caltech October 9, 2001
Columbia University/Nevis Labs
Raphael Galea
Basic Design
http://www.nevis.columbia.edu/~galea/mucos
Cool Muon Colliders:
Caltech October 9, 2001
Columbia University/Nevis Labs
Raphael Galea
Muon Motion in Cooling Cell
http://www.nevis.columbia.edu/~galea/mucos
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
Peripheral
Central
http://www.nevis.columbia.edu/~galea/mucos
Cool Muon Colliders:
Caltech October 9, 2001
Columbia University/Nevis Labs
Raphael Galea
Magnet Capture
Peripheral
Central
p+,m+
p
p+
pm+
m-
• +ve & -ve in same channel
p
p-,m-
•Separate charges at source
http://www.nevis.columbia.edu/~galea/mucos
Cool Muon Colliders:
Caltech October 9, 2001
Columbia University/Nevis Labs
Raphael Galea
Phase Rotation
• Apply simple E-field
form :
Emax
• Optimize muon yield
as a function of t1,t2
& Length of the phase
rotation region
http://www.nevis.columbia.edu/~galea/mucos
t1
t2
Cool Muon Colliders:
Caltech October 9, 2001
Columbia University/Nevis Labs
Raphael Galea
http://www.nevis.columbia.edu/~galea/mucos
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
http://www.nevis.columbia.edu/~galea/mucos
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
http://www.nevis.columbia.edu/~galea/mucos
Cool Muon Colliders:
Caltech October 9, 2001
Columbia University/Nevis Labs
Raphael Galea
Nevis Setup
http://www.nevis.columbia.edu/~galea/mucos
Cool Muon Colliders:
Caltech October 9, 2001
Columbia University/Nevis Labs
Raphael Galea
Simulation @ Nevis
• Vary E-field, density
& length of gas cell
• Simulation with no
Multiple Scattering
• E-field parallel to Bfield so muons do not
stop
http://www.nevis.columbia.edu/~galea/mucos
Cool Muon Colliders:
Caltech October 9, 2001
Columbia University/Nevis Labs
Raphael Galea
http://www.nevis.columbia.edu/~galea/mucos
Cool Muon Colliders:
Caltech October 9, 2001
Columbia University/Nevis Labs
Raphael Galea
http://www.nevis.columbia.edu/~galea/mucos
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 m- capture cross section at low
energies in He & H2
http://www.nevis.columbia.edu/~galea/mucos
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
http://www.nevis.columbia.edu/~galea/mucos
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 mhttp://www.nevis.columbia.edu/~galea/mucos
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, 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
http://www.nevis.columbia.edu/~galea/mucos