the international linear collider barry barish 15-nov-05
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The International Linear Collider
Barry Barish15-Nov-05
15-Nov-05 BNL Physics Colloquium 2
Particle Physics Inquiry Based Science
1. Are there undiscovered principles of nature:New symmetries, new physical laws?
2. How can we solve the mystery of dark energy?
3. Are there extra dimensions of space?
4. Do all the forces become one?
5. Why are there so many kinds of particles?
6. What is dark matter?How can we make it in the laboratory?
7. What are neutrinos telling us?
8. How did the universe come to be?
9. What happened to the antimatter?from the Quantum Universe
15-Nov-05 BNL Physics Colloquium 3
Answering the QuestionsThree Complementary Probes
• Neutrinos as a Probe– Particle physics and astrophysics using a weakly
interacting probe
• High Energy Proton Proton Colliders– Opening up a new energy frontier ( ~ 1 TeV scale)
• High Energy Electron Positron Colliders– Precision Physics at the new energy frontier
15-Nov-05 BNL Physics Colloquium 4
Neutrinos observed from the sun !
Davis and Bahcall
Koshiba41H 4He + 2e+ + 2 ve + energy
SuperKamiokande
15-Nov-05 BNL Physics Colloquium 5
But, too few neutrinos …
If neutrinos have mass, then as conjectured earlier by Bruno Pontecorvo, neutrinos could “oscillate” from one type to another.
In this case, some of the original electron neutrinos made in the sun convert to other neutrinos on trajectory to the earth
15-Nov-05 BNL Physics Colloquium 6
Puzzle resolved … neutrinos oscillate
SNO (Canada) used D20 to detect other neutrino types
KamLAND used terrestrialneutrinos from reactors, observes oscillations
15-Nov-05 BNL Physics Colloquium 7
Dark Energy 70%
Cold Dark Matter
20%
Ordinary (baryonic)
Matter 5%
Hot Dark MatterHot Dark Matter
(neutrinos) < 5%(neutrinos) < 5%
Neutrinos – Some of the Dark Matter!
Dark Energy
70%
15-Nov-05 BNL Physics Colloquium 8
Neutrinos – The Future
• Long baseline neutrino experiments – Create neutrinos at an accelerator or reactor and study at long distance when they have oscillated from one type to another.
MINOS
Opera
15-Nov-05 BNL Physics Colloquium 9
Neutrinos – Many Questions
• Why are neutrino masses so small ? • Are the neutrinos their own antiparticles?• What is the separation and ordering of the
masses of the neutrinos?• Neutrinos contribution to the dark matter?
• CP violation in neutrinos, leptogenesis, possible role in the early universe and in understanding the particle antiparticle asymmetry in nature?
15-Nov-05 BNL Physics Colloquium 10
Why a TeV Scale e+e- Accelerator?
• Two parallel developments over the past few years (the science & the technology)
– The precision information from LEP and other data have pointed to a low mass Higgs; Understanding electroweak symmetry breaking, whether supersymmetry or an alternative, will require precision measurements.
– There are strong arguments for the complementarity between a ~0.5-1.0 TeV ILC and the LHC science.
15-Nov-05 BNL Physics Colloquium 11
Electroweak Precision Measurements
What causes mass??
0
2
4
6
10020 400
mH GeV
Excluded Preliminary
had =(5)
0.027610.00036
0.027470.00012
Without NuTeV
theory uncertainty
Winter 2003
The mechanism – Higgs or alternative appears around the corner
15-Nov-05 BNL Physics Colloquium 12
Accelerators and the Energy FrontierLarge Hadron Collider
CERN – Geneva Switzerland
15-Nov-05 BNL Physics Colloquium 13
LHC and the Energy FrontierSource of Particle Mass
The Higgs FieldDiscover the Higgs
or variants or ???
fb-1
LEP
FNAL
15-Nov-05 BNL Physics Colloquium 14
LHC and the Energy FrontierA New Force in Nature
Discover a new heavy particle, Z’
Can show by measuring the couplings with the ILC how it relates to other particles and forces
15-Nov-05 BNL Physics Colloquium 15
This led to higher energy machines: Electron-Positron Colliders
Bruno Touschek built the first successful electron-positron collider at Frascati, Italy (1960)
Eventually, went up to 3 GeV
ADA
15-Nov-05 BNL Physics Colloquium 16
But, not quite high enough energy ….
DiscoveryOf
CharmParticles
and
3.1 GeV
Burt RichterNobel Prize
SPEAR at SLAC
15-Nov-05 BNL Physics Colloquium 17
The rich history for e+e- continued as higher energies were achieved …
DESY PETRA Collider
15-Nov-05 BNL Physics Colloquium 18
Electron Positron CollidersThe Energy Frontier
15-Nov-05 BNL Physics Colloquium 19
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-05 BNL Physics Colloquium 20
The linear collider will measure the spin of any Higgs it can produce by measuring the energy dependence from threshold
How do you know you have discovered the Higgs ?
Measure the quantum numbers. The Higgs must have spin zero !
15-Nov-05 BNL Physics Colloquium 21
What can we learn from the Higgs?
•Straight blue line gives the standard model predictions.
• Range of predictions in models with extra dimensions -- yellow band, (at most 30% below the Standard Model
• The red error bars indicate the level of precision attainable at the ILC for each particle
Precision measurements of Higgs coupling can reveal extra dimensions in nature
15-Nov-05 BNL Physics Colloquium 22
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-05 BNL Physics Colloquium 23
Bosons Fermions
Virtues of Supersymmetry:– Unification of Forces– The Hierarchy Problem– Dark Matter
…
Is There a New Symmetry in Nature? Supersymmetry
15-Nov-05 BNL Physics Colloquium 24
Parameters for the ILC
• Ecm adjustable from 200 – 500 GeV
• Luminosity ∫Ldt = 500 fb-1 in 4 years
• Ability to scan between 200 and 500 GeV
• Energy stability and precision below 0.1%
• Electron polarization of at least 80%
• The machine must be upgradeable to 1 TeV
15-Nov-05 BNL Physics Colloquium 25
A TeV Scale e+e- Accelerator?
• Two parallel developments over the past few years (the science & the technology)
– Two alternate designs -- “warm” and “cold” had come to the stage where the show stoppers had been eliminated and the concepts were well understood.
– A major step toward a new international machine requires uniting behind one technology, and then make a unified global design based on the recommended technology.
15-Nov-05 BNL Physics Colloquium 26
• The JLC-X and NLC essentially a unified single design with common parameters
• The main linacs based on 11.4 GHz, room temperature copper technology.
GLC GLC/NLC Concept
15-Nov-05 BNL Physics Colloquium 27
TESLA Concept
• The main linacs based on 1.3 GHz superconducting technology operating at 2 K.
• The cryoplant, is of a size comparable to that of the LHC, consisting of seven subsystems strung along the machines every 5 km.
15-Nov-05 BNL Physics Colloquium 28
CLIC Concept
The main linac rfpower is produced by decelerating a high-current (150 A) low-energy (2.1 GeV) drive beam
Nominal accelerating gradient of 150 MV/m
GOALProof of concept ~2010
Drive Beam
Main Accelerator
15-Nov-05 BNL Physics Colloquium 29
SCRF Technology Recommendation
• The recommendation of ITRP was presented to ILCSC & ICFA on August 19, 2004 in a joint meeting in Beijing.
• ICFA unanimously endorsed the ITRP’s recommendation on August 20, 2004
15-Nov-05 BNL Physics Colloquium 30
The ITRP Recommendation
• We recommend that the linear collider be based on superconducting rf technology
– 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).
15-Nov-05 BNL Physics Colloquium 31
The Community Self-Organized
Nov 13-15, 2004
15-Nov-05 BNL Physics Colloquium 32
Global Design Effort
– The Mission of the GDE • Produce a design for the ILC that includes a
detailed design concept, performance assessments, reliable international costing, an industrialization plan , siting analysis, as well as detector concepts and scope.
• Coordinate worldwide prioritized proposal driven R & D efforts (to demonstrate and improve the performance, reduce the costs, attain the required reliability, etc.)
15-Nov-05 BNL Physics Colloquium 33
GDE MembersChris Adolphsen, SLACJean-Luc Baldy, CERNPhilip Bambade, LAL, OrsayBarry Barish, CaltechWilhelm Bialowons, DESYGrahame Blair, Royal HollowayJim Brau, University of OregonKarsten Buesser, DESYElizabeth Clements, FermilabMichael Danilov, ITEPJean-Pierre Delahaye, CERN, Gerald Dugan, Cornell UniversityAtsushi Enomoto, KEKBrian Foster, Oxford UniversityWarren Funk, JLABJie Gao, IHEPTerry Garvey, LAL-IN2P3Hitoshi Hayano, KEKTom Himel, SLACBob Kephart, FermilabEun San Kim, Pohang Acc LabHyoung Suk Kim, Kyungpook Nat’l UnivShane Koscielniak, TRIUMFVic Kuchler, FermilabLutz Lilje, DESY
Tom Markiewicz, SLACDavid Miller, Univ College of LondonShekhar Mishra, FermilabYouhei Morita, KEKOlivier Napoly, CEA-SaclayHasan Padamsee, Cornell UniversityCarlo Pagani, DESYNan Phinney, SLACDieter Proch, DESYPantaleo Raimondi, INFNTor Raubenheimer, SLACFrancois Richard, LAL-IN2P3Perrine Royole-Degieux, GDE/LALKenji Saito, KEKDaniel Schulte, CERNTetsuo Shidara, KEKSasha Skrinsky, Budker InstituteFumihiko Takasaki, KEKLaurent Jean Tavian, CERNNobu Toge, KEKNick Walker, DESYAndy Wolski, LBLHitoshi Yamamoto, Tohoku UnivKaoru Yokoya, KEK
49 members
Americas 16 Europe 21 Asia 12
15-Nov-05 BNL Physics Colloquium 34
main linacbunchcompressor
dampingring
source
pre-accelerator
collimation
final focus
IP
extraction& dump
KeV
few GeV
few GeVfew GeV
250-500 GeV
Designing a Linear Collider
Superconducting RF Main Linac
15-Nov-05 BNL Physics Colloquium 35
rf bands:
L-band (TESLA) 1.3 GHz = 3.7 cm
S-band (SLAC linac) 2.856 GHz 1.7 cm
C-band (JLC-C) 5.7 GHz 0.95 cm
X-band (NLC/GLC) 11.4 GHz 0.42 cm
(CLIC) 25-30 GHz 0.2 cm
Accelerating structure size is dictated by wavelength of the rf accelerating wave. Wakefields related to structure size; thus so is the difficulty in controlling emittance growth and final luminosity.
Bunch spacing, train length related to rf frequency
Damping ring design depends on bunch length, hence frequency
Specific Machine Realizations
Frequency dictates many of the design issues for LC
RF Bands
15-Nov-05 BNL Physics Colloquium 36
Design Approach
• Create a baseline configuration for the machine– Document a concept for ILC machine with a complete
layout, parameters etc. defined by the end of 2005– Make forward looking choices, consistent with attaining
performance goals, and understood well enough to do a conceptual design and reliable costing by end of 2006.
– Technical and cost considerations will be an integral part in making these choices.
– Baseline will be put under “configuration control,” with a defined process for changes to the baseline.
– A reference design will be carried out in 2006. I am proposing we use a “parametric” design and costing approach.
– Technical performance and physics performance will be evaluated for the reference design
15-Nov-05 BNL Physics Colloquium 37
Parametric Approach
• Parametric approach to design– machine parameters : a space to optimize the machine
– Trial parameter space, being evaluated by subsystems
– machine design : incorporate change without redesign; incorporates value engineering, trade studies at each step to minimize costs
15-Nov-05 BNL Physics Colloquium 38
Approach to ILC R&D Program
• Proposal-driven R&D in support of the baseline design. – Technical developments, demonstration experiments,
industrialization, etc.
• Proposal-driven R&D in support of alternatives to the baseline– Proposals for potential improvements to the baseline,
resources required, time scale, etc.
• Develop a prioritized DETECTOR R&D program aimed at technical developments needed to reach combined design performance goals
15-Nov-05 BNL Physics Colloquium 39
The Key Decisions
Critical choices: luminosity parameters & gradient
15-Nov-05 BNL Physics Colloquium 40
Making Choices – The Tradeoffs
Many decisions are interrelated and require input from several WG/GG groups
15-Nov-05 BNL Physics Colloquium 41
Superconducting RF Cavities
High Gradient Accelerator35 MV/meter -- 40 km linear collider
15-Nov-05 BNL Physics Colloquium 42
Improved Cavity Shapes
15-Nov-05 BNL Physics Colloquium 43
Improved Fabrication
15-Nov-05 BNL Physics Colloquium 44
Improved ProcessingElectropolishing
Chemical Polish
Electro Polish
15-Nov-05 BNL Physics Colloquium 45
(Improve surface quality -- pioneering work done at KEK)
BCP EP
• Several single cell cavities at g > 40 MV/m
• 4 nine-cell cavities at ~35 MV/m, one at 40 MV/m
• Theoretical Limit 50 MV/m
Electro-polishing
15-Nov-05 BNL Physics Colloquium 46
Gradient
Results from KEK-DESY collaboration
must reduce spread (need more statistics)
single
-cell
measu
rem
ents
(in
nin
e-c
ell
cavit
ies)
15-Nov-05 BNL Physics Colloquium 47
Baseline Gradient
15-Nov-05 BNL Physics Colloquium 48
Large Grain Single Crystal Nb Material
15-Nov-05 BNL Physics Colloquium 49
ILC Siting and Conventional Facilities
• The design is intimately tied to the features of the site– 1 tunnels or 2 tunnels?– Deep or shallow?– Laser straight linac or follow earth’s curvature in
segments?
• GDE ILC Design will be done to samples sites in the three regions – North American sample site will be near Fermilab– Japan and Europe are to determine sample sites by the
end of 2005
15-Nov-05 BNL Physics Colloquium 50
1 vs 2 Tunnels
• Tunnel must contain– Linac Cryomodule– RF system– Damping Ring Lines
• Save maybe $0.5B
• Issues– Maintenance– Safety– Duty Cycle
15-Nov-05 BNL Physics Colloquium 51
Possible Tunnel Configurations
• One tunnel of two, with variants ??
15-Nov-05 BNL Physics Colloquium 52
ILC Civil Program
Civil engineers from all three regions working to develop methods of analyzing the siting issues and comparing sites.
The current effort is not intended to select a potential site, but rather to understand from the beginning how the features of sites will effect the design, performance and cost
15-Nov-05 BNL Physics Colloquium 53
Beam Detector Interface
TauchiLCWS05
15-Nov-05 BNL Physics Colloquium 54
• “Our task is to continue studies on physics at the linear collider more precisely and more profoundly, taking into account progresses in our field, as well as on developments of detector technologies best suited for the linear collider experiment. As we know from past experiences, this will be enormously important to realize the linear collider.”
• Akiya Miyamoto
ACFA Joint Linear Collider Physics and Detector Working
Group
15-Nov-05 BNL Physics Colloquium 55
Accelerator Physics Challenges• Develop High Gradient Superconducting RF systems
– Requires efficient RF systems, capable of accelerating high power beams (~MW) with small beam spots(~nm).
• Achieving nm scale beam spots – Requires generating high intensity beams of electrons and
positrons– Damping the beams to ultra-low emittance in damping rings– Transporting the beams to the collision point without significant
emittance growth or uncontrolled beam jitter– Cleanly dumping the used beams.
• Reaching Luminosity Requirements– Designs satisfy the luminosity goals in simulations– A number of challenging problems in accelerator physics and
technology must be solved, however.
15-Nov-05 BNL Physics Colloquium 56
Test Facility at KEK
15-Nov-05 BNL Physics Colloquium 57
Test Facility at SLAC
15-Nov-05 BNL Physics Colloquium 58
TESLA Test Facility Linac - DESY
laser driven electron gun
photon beam diagnostics
undulatorbunch
compressor
superconducting accelerator modules
pre-accelerator
e- beam diagnostics
e- beam diagnostics
240 MeV 120 MeV 16 MeV 4 MeV
15-Nov-05 BNL Physics Colloquium 59
Fermilab ILC SCRF Program
International Linear Collider Timeline
2005 2006 2007 2008 2009 2010
Global Design Effort Project
Baseline configuration
Reference Design
ILC R&D Program
Technical Design
Expression of Interest to Host
International Mgmt
15-Nov-05 BNL Physics Colloquium 61
Conclusions• We have determined a number of very fundamental
physics questions to answer, like ….– What determines mass?– What is the dark matter?– Are there new symmetries in nature?– What explains the baryon asymmetry?– Are the forces of nature unified
• We are developing the tools to answer these questions and discover new ones– Neutrino Physics– Large Hadron Collider– International Linear Collider
• The next era of particle physics will be very exciting
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