Upload
portia
View
25
Download
1
Tags:
Embed Size (px)
DESCRIPTION
The Future of Accelerator Based Particle Physics. Barry Barish Czech Technical University 15-Nov-11. Path to higher energy. Collider History: Energy constantly increasing with time Hadron Collider at the energy frontier Lepton Collider for precision physics - PowerPoint PPT Presentation
Citation preview
Future Lepton Collider 1
Barry BarishCzech Technical
University15-Nov-11
The Future of Accelerator Based Particle Physics
15-Nov-11 Czech Technical University
Path to higher energy
Collider History: Energy constantly increasing with timeo Hadron Collider at the
energy frontiero Lepton Collider for
precision physics
Consensus to build Linear Collider with Ecm > 500 GeV to complement LHC physics
15-Nov-11 Czech Technical University
Future Lepton Collider 2
15-Nov-11 Czech Technical University
Future Lepton Collider 33
Three Generations: Complementarity
DiscoveryOf
CharmParticles
and
3.1 GeV
Burt RichterNobel Prize
SPEAR at SLAC
First generation
15-Nov-11 Czech Technical University
Future Lepton Collider 44
Rich History of Discovery
DESY PETRA Collider
Second generation
Future Lepton Collider 55
Precision Measurements
CERN’s LEP Collider set the stage for
Terascale physics
0
2
4
6
10020 400
mH GeV
Excluded Preliminary
had =(5)
0.027610.00036
0.027470.00012
Without NuTeV
theory uncertainty
Winter 2003
• Reveal the origin of quark and lepton mass
• Produce dark matter in the laboratory
• Test exotic theories of space and time
Third generation
15-Nov-11 Czech Technical University
15-Nov-11 Czech Technical University
Future Lepton Collider 66
SPEAR
PETRA
LEP
EN
ER
GY
YEAR 2020+
1 Te
V ILC (or CLIC)
1970
1 Ge
V
Fourthgeneration?
Three Generations of Successful e+e- Colliders
The Energy Frontier
15-Nov-11 Czech Technical University
Future Lepton Collider 77
The next big accelerator: a lepton collider?
• Terascale science and how a lepton collider will complement the LHC?
• Electron-Positron: Why linear? What technology to employ?
• An option with muons?
• Designing the ILC -- a new paradigm in international collaboration.
• A thumbnail description of the ILC Reference Design and Cost?
• Present program and plans
15-Nov-11 Czech Technical University
Future Lepton Collider 88
Exploring the TerascaleThe Tools
• The LHC– It will lead the way and has large reach– Quark-quark, quark-gluon and gluon-gluon
collisions at 0.5 - 5 TeV– Broadband initial state
• The ILC– A second view with high precision– Electron-positron collisions with fixed energies,
adjustable between 0.1 and 1.0 TeV– Well defined initial state
• Together, these are our tools for the Terascale
15-Nov-11 Czech Technical University
Future Lepton Collider 99
Why e+e- Collisions?
• Elementary particles
• Well-defined
– energy
– angular momentum
• Uses full COM energy
• Produces particles democratically
• Can mostly fully reconstruct events
15-Nov-11 Czech Technical University
Future Lepton Collider 10
Comparison: ILC and LHC
ILC LHC
Beam Particle : Electron x Positron Proton x Proton
CMS Energy : 0.5 – 1 TeV 14 TeV
Luminosity Goal : 2 x 1034 /cm2/sec 1 x1034 /cm2/sec
Accelerator Type : Linear Circular Storage Rings
Technology : Supercond. RF Supercond. Magnet
15-Nov-11 Czech Technical University
Future Lepton Collider 11
LHC ILCe+ e– Z H Z e+ e–, H b …
Higgs event Simulation Comparison
b
15-Nov-11 Czech Technical University
Future Lepton Collider 1212
Higgs Signal with LHC
Rare decay channel: BR~10-3
Projected signal and background after data cuts to optimize signal to background
Background large: S/B 1:20, but can estimate from non signal areas
CMS
15-Nov-11 Czech Technical University
Future Lepton Collider 13
Precision Higgs physics
Model-independent Studies
• mass
• absolute branching ratios
• total width
• spin
• top Yukawa coupling
• self coupling
Precision MeasurementsGarcia-Abia et al
15-Nov-11 Czech Technical University
Future Lepton Collider 14
Higgs Coupling-mass relation
ii vm
Remember - the Higgs is a Different!
• It is a zero spin particle that fills the vacuum
• It couples to mass; masses and decay rates are related
15-Nov-11 Czech Technical University
Future Lepton Collider 15
The linear collider will measure the spin of any Higgs it can produce by measuring the energy dependence from threshold
ILC: Is it really the Higgs ?
Measure the quantum numbers. The Higgs must have spin zero !
15-Nov-11 Czech Technical University
Future Lepton Collider 16
What can we learn from the Higgs?
Precision measurements of Higgs coupling
Higgs Coupling strength is proportional to Mass
15-Nov-11 Czech Technical University
Future Lepton Collider 17
e+e- : Studying the Higgsdetermine the
underlying model
SM 2HDM/MSSM
Yamashita et al Zivkovic et al
15-Nov-11 Czech Technical University
Future Lepton Collider 18
- Measure quantum numbers
- Is it MSSM, NMSSM, …?
- How is it broken?
ILC can answer these questions!
- tunable energy
- polarized beams
Supersymmetry at ILC
e+e- production crosssections
15-Nov-11 Czech Technical University
Future Lepton Collider 19
ILC Supersymmetry
Two methods to obtain absolute sparticle masses:
In the continuumKinematic Threshold:
Minimum and maximum determines masses of primary slepton and secondary neutralino/chargino
Determine SUSY parameters without model assumptions
Martyn
Freitas
15-Nov-11 Czech Technical University
Future Lepton Collider 20
• The abundance of the LSP as dark matter can be precisely calculated, if the mass and particle species are given.
• ILC can precisely measure the mass and the coupling of the LSP
• The Dark Matter density in the universe and in our Galaxy can be calculated.
The most attractive candidate for the dark matter is the lightest SUSY particle
Dark Matter CandidatesLSP
15-Nov-11 Czech Technical University
Future Lepton Collider 21
New space-time dimensions can be mapped by studying the emission of gravitons into the extra dimensions, together with a photon or jets emitted into the normal dimensions.
Linear collider
Direct production from extra dimensions ?
15-Nov-11 Czech Technical University
Future Lepton Collider 22
Possible TeV Scale Lepton Colliders
ILC < 1 TeVTechnically possible
~ 2020 +
QUADQUAD
POWER EXTRACTIONSTRUCTURE
BPM
ACCELERATINGSTRUCTURES
CLIC < 3 TeVFeasibility?
Longer timescaleMain beam – 1 A, 200 ns from 9 GeV to 1.5 TeV
Drive beam - 95 A, 300 nsfrom 2.4 GeV to 240 MeV
Muon Collider < 4 TeV
FEASIBILITY??Much longer timescale
Much R&D Needed• Neutrino Factory R&D +• bunch merging• much more cooling• etc
ILC
CLIC
Muon Collider
15-Nov-11 Czech Technical University
Future Lepton Collider 23
ILC Baseline DesignILC Baseline Design
250
250 Gev 250 Gev
e+ e- Linear ColliderEnergy 250 Gev x 250 GevLength 11 + 11 km# of RF units 560# of cryomodules 1680# of 9-cell cavities 145602 Detectors push-pull2e34 peak luminosity5 Hz rep rate, 1000 -> 6000 bunches per cycleIP spots sizes: x 350 – 620 nm; y 3.5 – 9.0 nm
15-Nov-11 Czech Technical University
Future Lepton Collider 24
RDR Design Parameters
Max. Center-of-mass energy 500 GeV
Peak Luminosity ~2x1034 1/cm2s
Beam Current 9.0 mA
Repetition rate 5 Hz
Average accelerating gradient 31.5 MV/m
Beam pulse length 0.95 ms
Total Site Length 31 km
Total AC Power Consumption ~230 MW
Future Lepton Collider 2525
E ~ (E4 /m4 R)
Linear implies single passcost
Energy
CircularCollider Linear
ColliderR Synchrotron
Radiation
R
~ 200 GeV
< 5 nm vertical
• Low emittance (high brightness) machine optics• Contain emittance growth• Squeeze the beam as small as possible at collision point
15-Nov-11 Czech Technical University
15-Nov-11 Czech Technical University
Future Lepton Collider 2626
ILC – Underlying Technology
• Room temperature copper structures
OR
• Superconducting RF cavities
15-Nov-11 Czech Technical University
Future Lepton Collider 2727
SCRF Technology Recommendation
• The recommendation of ITRP was presented to ILCSC & ICFA on August 19, 2004 in a joint meeting
in Beijing. • This recommendation is made
with the understanding that we are recommending a technology, not a design. We expect the final design to be developed by a team drawn from the combined warm and cold linear collider communities, taking full advantage of the experience and expertise of both (from the Executive Summary). This led to the formation of the Global Design Effort (GDE)
ICFA unanimously endorsed the ITRP’s recommendation on August 20, 2004
Strong international interest in developing SCRF technology
15-Nov-11 Czech Technical University
Future Lepton Collider 2828
main linacbunchcompressor
dampingring
source
pre-accelerator
collimation
final focus
IP
extraction& dump
KeV
few GeV
few GeVfew GeV
250-500 GeV
GDE -- Designing a Linear Collider
Superconducting RF Main Linac
Traveling wave structures• NC standing wave structures would have high Ohmic losses• => traveling wave structures
• RF ‘flows’ with group velocity vG along the structureinto a load at the structure exit
• Condition for acceleration: Δφ=d·ω/c (Δφ cell phase difference)• Shorter fill time Tfill= 1/vG dz - order <100 ns compared to ~ms for
SC RF
pulsed RFPowersource
d
RF load
particles “surf” the electromagnetic wave
15-Nov-11 Czech Technical University
Future Lepton Collider 29
CLIC (Compact Linear Collider)
15-Nov-11 Czech Technical University
Future Lepton Collider 30
QUAD
QUAD
POWER EXTRACTIONSTRUCTURE
BPM
ACCELERATINGSTRUCTURES
Drive beam - 95 A, 300 nsfrom 2.4 GeV to 240 MeV
Main beam – 1 A, 200 ns from 9 GeV to 1.5 TeV
Room Temperature RF
CLIC – in a nutshell
• CompactLinearCollider
• e+/e- colliderfor up to 3 TeV
• Luminosity 6·1034cm-2s-1 (3 TeV)
• Normal conducting RF accelerating structures
• Gradient 100 MV/m• RF frequency 12 GHz• Two beam acceleration principle for cost minimisation and efficiency• Many common points with ILC, similar elements, but different parameters
15-Nov-11 Czech Technical University
Future Lepton Collider 31
Test results
Accelerating structure developments
• Structures built from discs• Each cell damped by 4 radial
WGs• terminated by SiC RF loads• Higher order modes (HOM)
enter WG • Long-range wakefields
efficiently damped15-Nov-11 Czech Technical University
Future Lepton Collider 32
CLIC: Why 100 MV/m and 12 GHz ? • Optimisation - figure of merit:
– Luminosity per linac input power
• Structure limits: – RF breakdown – scaling
(Esurf<260MV/m , P/Cτ1/3 limited)– RF pulse heating (ΔT<56°K)
• Beam dynamics:– emittance preservation – wake
fields– Luminosity, bunch population,
bunch spacing– efficiency – total power
• take into account cost model
after > 60 * 106 structures:100 MV/m 12 GHz chosen,
previously 150 MV/m, 30 GHzA.Grudiev15-Nov-11
Czech Technical UniversityFuture Lepton Collider 33
Muon Collider A muon collider is an attractive multi-TeV lepton collider option, because muons do not radiate as readily as electrons (m / me ~ 207):- COMPACT Fits on laboratory site- MULTI-PASS ACCELERATION Cost Effective operation & construction- MULTIPASS COLLISIONS IN A RING (~1000 turns) Relaxed emittance requirements & hence relaxed tolerances- NARROW ENERGY SPREAD Precision scans, kinematic constraints- TWO DETECTORS (2 IPs)-Tbunch ~ 10 s … (e.g. 4 TeV collider) Lots of time for readout Backgrounds don’t pile up- (m/me)2 = ~40000 Enhanced s-channel rates for Higgs-like particles
A 4 TeV Muon Collider wouldfit on the Fermilab Site
3415-Nov-11 Czech Technical University
Future Lepton Collider
Challenges
• Muons are produced as tertiary particles. To make enough of them requires a MW scale proton source & target facility.
• Muons decay everything must be done fast and we must deal with the decay electrons (& neutrinos for CM energies above ~3 TeV).
• Muons are born within a large phase-space. For a Muon Collider, it must be cooled by O(106) before they decay New cooling technique (ionization cooling) must be demonstrated, and it requires components with demanding performance
• After cooling, beams still have relatively large emittance.
3515-Nov-11 Czech Technical University
Future Lepton Collider
MUON COLLIDER SCHEMATIC
Proton source: Example: upgraded PROJECT X (4 MW, 2±1 ns long bunches)
1021 muons per year that fit within the acceptance of an accelerator:N=6000 m//N=25 mm
√s = 3 TeV Circumference = 4.5kmL = 3×1034 cm-2s-1 /bunch = 2x1012
(p)/p = 0.1%N = 25 m, //N=70 mm* = 5mmRep Rate = 12Hz
3615-Nov-11 Czech Technical University
Future Lepton Collider
Muon Collider cf. Neutrino Factory
NEUTRINOFACTORY
MUONCOLLIDER
In present MC baseline design, Front End is same as for NF(although the optimal initial coolers might ultimately be different)
3715-Nov-11 Czech Technical University
Future Lepton Collider
Muon Collider: Ionization Cooling
TRANSVERSE COOLING: Muons lose energy by in material (dE/dx). Re-accelerate in longitudinal direction reduce transverse emittance. Coulomb scattering heats beam low Z absorber.
LONGITUDINAL COOLING: Mix transverse & longitudinal degrees of freedom during cooling. Can be done in helical solenoids.
FINAL COOLING: To get the smallest achievable transverse emittance, over-cool the longitudinal emittance, and then reduce transverse emittance letting the longitudinal phase space grow.
εt,
,N
(m
)
Liq. H2 Liq. H2 Liq. H2
RF RF
RF
liquid H
2solenoid
High Field (HTS) Solenoids
38
More detailabout optionsin R. Palmer’stalk
15-Nov-11 Czech Technical University
Future Lepton Collider
Muon Beam
Spectro-
meter
Cooling
section
Spectro-
meter
MICE – upstream beamline
- Tests short cooling section, in muon beam, measuring the muons before & after the cooling section. one at a time.
- Learn about cost, complexity, & engineeringissues associated with cooling channels.
-Vary RF, solenoid & absorber parameters & demonstrate ability to simulate response of muons
Muon Ionization Cooling Experiment (MICE)
3915-Nov-11 Czech Technical University
Future Lepton Collider
Muon Collider Detectors
Unique to a Muon Collider are detector backgrounds from muon decay.
For TeV muon decays, the electron decay angles are O(10) mradians . Electrons typically stay inside beampipe for few meters. Hence decay electrons born within a few meters of the IP are benign.
Shielding strategy: sweep the electrons born further than ~6m from the IP into ~6m of shielding
40
Map of backgroundparticle densities in detector
15-Nov-11 Czech Technical University
Future Lepton Collider
International Linear Collider
ILC
15-Nov-11 Czech Technical University
Future Lepton Collider 41
15-Nov-11 Czech Technical University
Future Lepton Collider 42
ILC --- Deep Underground
15-Nov-11 Czech Technical University
Future Lepton Collider 43
LHC --- Superconducting Magnet
15-Nov-11 Czech Technical University
Future Lepton Collider 44
ILC - Superconducting RF Cryomodule
15-Nov-11 Czech Technical University
Future Lepton Collider 45Global Design Effort 45
Major R&D Goals for Technical Design
Accelerator Design and Integration (AD&I) • Studies of possible cost reduction designs and
strategies for consideration in a re-baseline in 2010
SCRF• High Gradient R&D - globally coordinated program to
demonstrate gradient by 2010 with 50%yield;
ATF-2 at KEK
• Demonstrate Fast Kicker performance and Final Focus Design
Electron Cloud Mitigation – (CesrTA)• Electron Cloud tests at Cornell to establish mitigation
and verify one damping ring is sufficient.
15-Nov-11 Czech Technical University
Future Lepton Collider 46
Proposed Design changes for TDR
RDR SB2009 • Single Tunnel for main linac
•Move positron source to end of linac ***
• Reduce number of bunches factor of two (lower power) **
• Reduce size of damping rings (3.2km)
• Integrate central region
•Single stage bunch compressor
15-Nov-11 Czech Technical University
Future Lepton Collider 47
The ILC SCRF Cavity
- Achieve high gradient (35MV/m); develop multiple vendors; make cost effective, etc
- Focus is on high gradient; production yields; cryogenic losses; radiation; system performance
Global Plan for ILC Gradient R&D
14-Nov-11 PAC - Prague
Global Design Effort 48
New baseline gradient:Vertical acceptance: 35 MV/m average, allowing ±20% spread (28-42 MV/m)Operational: 31.5 MV/m average, allowing ±20% spread (25-38 MV/m)
14-Nov-11 PAC - Prague
Global Design Effort 49
Cavity Gradient Milestone Achieved
2010Milestone
TDRGoal
• Toward TDR goal• Field emission;
mechanical polishing• Other progress
15-Nov-11 Czech Technical University
Future Lepton Collider 50
15-Nov-11 Czech Technical University
Future Lepton Collider 51
Test Facilities: FLASHSCRF accelerator tests
15-Nov-11 Czech Technical University
Future Lepton Collider 52
Example Experimental Results
• Flat gradient solution achieved– 4.5 mA beam
• Characterisation of solution by scanning beam current– model benchmarking
Beam Current (mA)1 2 3 4 5
Gra
dien
t cha
nge
over
400
us (%
)
0
-3
-5
+3
+5
Gradient Tilts vs Beam Current (ACC7)
Intended working
point
~2.5%
15-Nov-11 Czech Technical University
Future Lepton Collider 53
FLASH: Stability
• 15 consecutive studies shifts (120hrs), and with no downtime
• Time to restore 400us bunch-trains after beam-off studies: ~10mins
• Energy stability with beam loading over periods of hours: ~0.02%
• Individual cavity “tilts” equally stable
Energy stability over 3hrs with 4.5mA
~0.02% pk-pk
9 Feb 2011
15-Nov-11 Czech Technical University
Future Lepton Collider 54
15-Nov-11 Czech Technical University
Future Lepton Collider 55
Test Facilities: ATF-2large international collaboration
ATF2 Goals:
A. Achievement of 37nm beam size• A1) Demonstration of a new compact final focus system;
– proposed by P.Raimondi and A.Seryi in 2000,
• A2) Maintenance of the small beam size– (several hours at the FFTB/SLAC)
B. Control of the beam position• B1) Demonstration of beam orbit stabilization with nano-
meter precision at IP.– (The beam jitter at FFTB/SLAC was about 40nm.)
• B2) Establishment of beam jitter controlling technique• at nano-meter level with ILC-like beam
15-Nov-11 Czech Technical University
Future Lepton Collider 56
15-Nov-11 Czech Technical University
Future Lepton Collider 57
ATF2 – Beam size/stability and kicker tests
IP Shintake Monitor
Final Doublet
5815-Nov-11 Czech Technical University
Future Lepton Collider
ATF / ATF2 After Earthquake?
15-Nov-11 Czech Technical University
Future Lepton Collider 59
See first reports in ILC Newsline 17-March-11Articles by Toshiaki Tauchi and Rika Takahashi
15-Nov-11 Czech Technical University
Future Lepton Collider 60
Test Facilities: Cesr-TA eCloudbroad accelerator applications
15-Nov-11 Czech Technical University
Future Lepton Collider 61
• Mitigating Electron Cloud
• Simulations – electrodes; coating and/or grooving vacuum pipe• Demonstration at CESR critical tests
eCloud R&D
15-Nov-11 Czech Technical University
Future Lepton Collider 62
15-Nov-11 Czech Technical University
Future Lepton Collider 63
CesrTA - Wiggler Observations
IWLC2010 - CERN, Geneva, Switzerland
0.002”radiusElectrode best performance
15-Nov-11 Czech Technical University
Future Lepton Collider 64
Field Region
Baseline Mitigation RecommendationAlternatives for
Further Investigation
Drift* TiN Coating Solenoid Windings NEG Coating
Dipole Grooves with TiN Coating
Antechambers for power loads and photoelectron control
R&D into the use of clearing electrodes.
Quadrupole*
TiN Coating R&D into the use of clearing electrodes or grooves with TiN coating
Wiggler Clearing Electrodes
Antechambers for power loads and photoelectron control
Grooves with TiN Coating
Proposed ILC Mitigation Scheme
15-Nov-11 Czech Technical University
Future Lepton Collider 65
Interaction Region
(old location)
Break point for push-pull disconnect
Provide reliable collisions of 5nm-small beams, with acceptable level of background, and be able to rapidly and efficiently exchange ~10kT detectors in a push-pull operation several times per year
15-Nov-11 Czech Technical University
Future Lepton Collider 66
Push – Pull Detector Concept
• Vibration stability will be one of the major criteria in eventual selection of a motion system design
Both detectors without platforms Both detectors with platforms
15-Nov-11 Czech Technical University
Future Lepton Collider 67
Detector Concepts Report
15-Nov-11 Czech Technical University
Future Lepton Collider 68
Detector Performance Goals
15-Nov-11 Czech Technical University
Future Lepton Collider 69
Detector Performance Goals
15-Nov-11 Czech Technical University
Future Lepton Collider 70
Detector Performance Goals
• ILC detector performance requirements and comparison to the LHC detectors:○ Inner vertex layer ~ 3-6 times closer to IP
○ Vertex pixel size ~ 30 times smaller
○ Vertex detector layer ~ 30 times thinner
Impact param resolution Δd = 5 [μm] + 10 [μm] / (p[GeV] sin 3/2θ)
○ Material in the tracker ~ 30 times less
○ Track momentum resolution ~ 10 times better
Momentum resolution Δp / p2 = 5 x 10-5 [GeV-1] central region
Δp / p2 = 3 x 10-5 [GeV-1] forward region
○ Granularity of EM calorimeter ~ 200 times better
Jet energy resolution ΔEjet / Ejet = 0.3 /√Ejet
Forward Hermeticity down to θ = 5-10 [mrad]
Future Lepton Collider 71
Final Reflections
• The energy frontier continues to be the primary tool to explore the central issues in particle physics
• The LHC at CERN will open the 1 TeV energy scale and we anticipate exciting new discoveries
• A companion lepton collider will be the logical next step, but such a machine has technical challenges and needs significant R&D and design now
• LHC results will inform the final design and even whether a higher energy options is needed, If so, this may also be possible, but on a longer time scale.
15-Nov-11 Czech Technical University