Dean Karlen University of Victoria & TRIUMF IPP Town Hall Meeting June 4, 2005, TRIUMF.

Dean KarlenUniversity of Victoria & TRIUMF

IPP Town Hall MeetingJune 4, 2005, TRIUMF

June 4, 2005June 4, 2005 The International Linear Collider / IPP Town Hall MeetingThe International Linear Collider / IPP Town Hall Meeting 33

The International Linear ColliderThe International Linear Collider Next in the line of eNext in the line of e++ee-- colliders at the high colliders at the high

energy frontier of particle physicsenergy frontier of particle physics

SLAC/SLC

CERN/LEP


year

1980 1990 2000 2010 2020 2030

Cen

tre-

of-m

ass

ener

gy (

GeV

)

100

1000PETRAPEPTRISTANSLCLEP - ILEP - IIILCILC - II

eeee colliders at the frontier colliders at the frontier

Z0 threshold

W+W threshold

tt thresholdHZ0 threshold?

dark matter threshold?


Why Linear?Why Linear?

Centre-of-mass Energy (GeV)

0 100 200 300 400 500 600

Circ

umfe

renc

e /

Leng

th (

km)

0

10

20

30

40

50

60

$

circular colliders

linear colliders

2ER

EL

A circular 500 GeVmachine would be170 km around andconsume 45 GW


““Energy Frontier” Particle PhysicsEnergy Frontier” Particle Physics

Increasing the collision energy allows for new Increasing the collision energy allows for new fundamental processes to be observed and probes fundamental processes to be observed and probes matter and space at smaller distance scalesmatter and space at smaller distance scales precision measurements sensitive to mass scales well above precision measurements sensitive to mass scales well above

ss The two main energy frontier tools in the past three The two main energy frontier tools in the past three

decades: proton colliders and electron collidersdecades: proton colliders and electron colliders protons are more easily accelerated to high energies protons are more easily accelerated to high energies

because they radiate less synchrotron radiation in a circular because they radiate less synchrotron radiation in a circular acceleratoraccelerator

electron interactions are more easily studied because the electron interactions are more easily studied because the initial state is simplerinitial state is simpler

both tools have been essential to advance our knowledge of both tools have been essential to advance our knowledge of fundamental physics:fundamental physics:

discoveries of new phenomenadiscoveries of new phenomena testing models that account for these phenomenatesting models that account for these phenomena


Interplay of proton and electron Interplay of proton and electron colliderscolliders

proton collidersproton colliders electron colliderselectron colliders1980’s: SppS• discovery of the Z0, W, W

1990’s: LEP/SLC• detailed investigation of Z0, W, W production• indirect influence of top quark – definitive prediction of its mass• indirect influence of Higgs boson – mass estimated

2010’s: ILC• detailed study of the Higgs• detailed study of dark matter

2000’s: LHC• discovery of the Higgs boson?• discovery of the dark matter particle?

1990’s: Tevatron• discovery of the top quark


Linear Collider Physics: ILinear Collider Physics: I The electromagnetic and weak forces are now The electromagnetic and weak forces are now

known to arise from a unifying symmetry in natureknown to arise from a unifying symmetry in nature most precisely demonstrated by the LEP/SLC experimentsmost precisely demonstrated by the LEP/SLC experiments

The symmetry between the electromagnetic and The symmetry between the electromagnetic and weak forces is broken (weak bosons are heavy)weak forces is broken (weak bosons are heavy) The Higgs model is an ad hoc component of the Standard The Higgs model is an ad hoc component of the Standard

Model that accounts for the broken symmetry – does not Model that accounts for the broken symmetry – does not explain whyexplain why

it works for low energy processes but falls apart at it works for low energy processes but falls apart at high energieshigh energies

the model predicts that a new particle exists (the the model predicts that a new particle exists (the Higgs boson) with definite propertiesHiggs boson) with definite properties

the ILC will be able to make a large variety of precision the ILC will be able to make a large variety of precision measurements that will provide critical data to measurements that will provide critical data to understand the real nature of electroweak symmetry understand the real nature of electroweak symmetry breakingbreaking


The golden processesThe golden processes At LEP, the golden processes for studying At LEP, the golden processes for studying

the electroweak sector were:the electroweak sector were:

At the ILC, the golden processes for At the ILC, the golden processes for studying the Higgs sector are:studying the Higgs sector are:

LEP beam energies were not sufficiently high LEP beam energies were not sufficiently high enough for these process to occurenough for these process to occur

0Zee WWee

HZee 0

Hee


Higgs production at a LCHiggs production at a LC


Linear Collider Physics: IILinear Collider Physics: II

From astrophysical observations, it appears From astrophysical observations, it appears that ~25% of the Universe is “Dark Matter”that ~25% of the Universe is “Dark Matter” neutral, stable, cold (massive), non-baryonicneutral, stable, cold (massive), non-baryonic new physics – a new (conserved) quantum new physics – a new (conserved) quantum

number?number? production and detection of dark matter production and detection of dark matter

particles at future colliders would be very particles at future colliders would be very exciting!exciting!

One possible explanation: supersymmetryOne possible explanation: supersymmetry not developed specifically to solve the DM not developed specifically to solve the DM

problem!problem! the LSP is an excellent candidate for DMthe LSP is an excellent candidate for DM


Dark Matter at the ILC?Dark Matter at the ILC?

There are strong hints that dark matter could be There are strong hints that dark matter could be produced at the ILCproduced at the ILC SUSY favours sparticle masses below ~ 1 TeVSUSY favours sparticle masses below ~ 1 TeV The dark matter density is consistent with a neutral The dark matter density is consistent with a neutral

particle having “weak” strength couplingsparticle having “weak” strength couplings The LHC has the best chance to discover The LHC has the best chance to discover

strongly interacting sparticles (gluinos, squarks)strongly interacting sparticles (gluinos, squarks) challenging study at LHC: initial state is not well challenging study at LHC: initial state is not well

known, final state involves a cascade of sparticle known, final state involves a cascade of sparticle decays, with at least two massive invisible particlesdecays, with at least two massive invisible particles

ILC can study the weakly interacting sparticlesILC can study the weakly interacting sparticles LHC+ILC data can “predict” DM relic density LHC+ILC data can “predict” DM relic density


ILC/LHC complementarity ILC/LHC complementarity

Well documented study underway:Well documented study underway: LHC/ILC Study Group:LHC/ILC Study Group:

http://www.ippp.dur.ac.uk/~georg/lhclc/http://www.ippp.dur.ac.uk/~georg/lhclc/ Recent document:Recent document:

““Physics Interplay of the LHC and the ILC”Physics Interplay of the LHC and the ILC” hep-ph / 0410364hep-ph / 0410364 470 pages:470 pages:

all cases: ILC + LHC data complementaryall cases: ILC + LHC data complementary

• Higgs Physics• Strong Electroweak Symmetry Breaking• Supersymmetric Models• Electroweak and QCD Precision Physics• New Gauge Theories• Models with Extra Dimensions


Consensus in the HEP communityConsensus in the HEP community

Given the broad range of fundamental Given the broad range of fundamental physics questions that it addresses, the physics questions that it addresses, the HEP community sees the ILC to be the HEP community sees the ILC to be the next step that is needed to advance the next step that is needed to advance the fieldfield over 2700 particle physicists have signed a over 2700 particle physicists have signed a

document supporting the physics potential of document supporting the physics potential of the ILCthe ILC

the US DOE places the ILC as the top priority the US DOE places the ILC as the top priority for mid-term new facilities for mid-term new facilities

committees for future accelerators committees for future accelerators (ICFA,ACFA,ECFA) also put the ILC as their first (ICFA,ACFA,ECFA) also put the ILC as their first prioritypriority


Building the ILCBuilding the ILC

Over the past decade, significant effort has Over the past decade, significant effort has gone into the necessary R&D to design a gone into the necessary R&D to design a linear collider to reach the required linear collider to reach the required specifications:specifications:

Centre of mass energy: 500 GeV – 1000 GeVCentre of mass energy: 500 GeV – 1000 GeV requires RF cavities with a large accelerating requires RF cavities with a large accelerating

gradient (>30 MeV/m)gradient (>30 MeV/m)

Luminosity: > 10Luminosity: > 103434 cm cmss

requires large numbers of electrons (> 10requires large numbers of electrons (> 101010) ) packed into very small bunches (< 500 x 5 nmpacked into very small bunches (< 500 x 5 nm22) ) brought into collision at high rate (> 10brought into collision at high rate (> 1044 s s))


Building the ILCBuilding the ILC

Two complete designs were prepared that Two complete designs were prepared that met these requirementsmet these requirements the key feature distinguishing them was the the key feature distinguishing them was the

nature of the RF accelerating cavities:nature of the RF accelerating cavities: US + Japan – high frequency, room temperatureUS + Japan – high frequency, room temperature Germany – lower frequency, superconductingGermany – lower frequency, superconducting

international technical review found both suitableinternational technical review found both suitable

In 2004, the International Technical In 2004, the International Technical Recommendation Panel selected the Recommendation Panel selected the superconducting optionsuperconducting option the world’s labs now working towards a single the world’s labs now working towards a single

designdesign


Superconducting accelerator cavitiesSuperconducting accelerator cavities


Possible Tunnel LayoutPossible Tunnel Layout

Need a 30 km tunnel to reach energy goalNeed a 30 km tunnel to reach energy goal


Damping ring R&DDamping ring R&D

ATF facility in Japan hasATF facility in Japan hasdemonstrated necessarydemonstrated necessaryreduction in emittancereduction in emittance


Final focus R&DFinal focus R&D


Linear collider detector conceptsLinear collider detector concepts

LDC

SiD

GLD

LDC: start from TESLA designCoordinators:• Ties Benke: Germany• Henri Videau: France• Marco Battaglia: USA• Dean Karlen: Canada• Bob Hsiung: Taiwan• Yasuhiro Sugimoto: JapanSee: www.ilcldc.org


Linear collider detector challengesLinear collider detector challenges Compared to the LHC, the ILC environment is Compared to the LHC, the ILC environment is

much less severe, but the performance much less severe, but the performance requirements are much more demanding:requirements are much more demanding:

Vertexing: Vertexing: ipip ~ 5 ~ 5 m m 5 5 m/(p sinm/(p sin3/23/2 )) 1/5 r1/5 rbeampipebeampipe, 1/30 pixel area, 1/30 thickness c.f. LHC, 1/30 pixel area, 1/30 thickness c.f. LHC

Tracking: Tracking: (1/p(1/ptt) ~ 5 ) ~ 5 ×10×10-5-5 GeV GeV-1-1

1/10 of LHC. 1/6 material in tracking volume1/10 of LHC. 1/6 material in tracking volume

Calorimetry: Calorimetry: EE ~ 0.3 ~ 0.3 EE 1/200 granularity of calorimeter c.f. LHC1/200 granularity of calorimeter c.f. LHC

1/3 SLD

1/10 LEP

1/2 LEP


Vertex detectorVertex detector Precise Si pixel detectors near the collision Precise Si pixel detectors near the collision

point point to detect the displaced vertex of particles to detect the displaced vertex of particles

coming from the decay of a particle with a very coming from the decay of a particle with a very short lifetime (less than 10short lifetime (less than 10 s) s)

examples: charm, bottom quarks, tau examples: charm, bottom quarks, tau leptonsleptons


Tracking detectorTracking detector


Tracking challengeTracking challenge Example: Higgs recoil massExample: Higgs recoil mass

(1/pt) ~ 5 ×10-5 GeV-1

is necessary!


Tracking technologyTracking technology Two technologies considered: Si (few Two technologies considered: Si (few

precise measuring layers) or gas precise measuring layers) or gas (continuous) (continuous)

Gas tracker: Time projection chamberGas tracker: Time projection chamber to achieve resolution goal requires an advance to achieve resolution goal requires an advance

in TPC technologyin TPC technology Canadian groupsCanadian groups

have made bighave made bigadvances towardsadvances towardsthis goal…this goal…


LC TPC R&D in CanadaLC TPC R&D in Canada

Prototype TPCs built to use MPGD readout:Prototype TPCs built to use MPGD readout: Carleton/Montreal group has Carleton/Montreal group has

pioneered the method of charge pioneered the method of charge dispersion with a resistive anode dispersion with a resistive anode for GEM and Micromegas TPC for GEM and Micromegas TPC readoutreadout

Victoria group has operated Victoria group has operated a GEM-TPC in magnetic a GEM-TPC in magnetic fields up to 5 Tfields up to 5 T

both prototypes have both prototypes have demonstrated significantly demonstrated significantly better resolution as compared to traditional TPCsbetter resolution as compared to traditional TPCs

see presentations on Wednesday at CAP congresssee presentations on Wednesday at CAP congress


Future plans for LC TPC R&D in CanadaFuture plans for LC TPC R&D in Canada

The Canadian group plans to The Canadian group plans to participate in test beam studies at KEK and participate in test beam studies at KEK and

DESYDESY participate in the design and construction of a participate in the design and construction of a

large scale prototype in collaboration with large scale prototype in collaboration with other groups from around the worldother groups from around the world

how to segment and tile MPGDs on a large how to segment and tile MPGDs on a large endplate?endplate?

perform simulation studies to answer questions perform simulation studies to answer questions arising in the detector conceptsarising in the detector concepts

pattern recognition in jetspattern recognition in jets how well can non-uniform magnetic fields be how well can non-uniform magnetic fields be

determined and corrected for? determined and corrected for?


CalorimeterCalorimeter


Jet Energy Resolution RequirementsJet Energy Resolution Requirements

Goal: distinguish W and Z when they decay into Goal: distinguish W and Z when they decay into quarksquarks requires excellent jet energy resolution, requires excellent jet energy resolution, EE ~ ~

30% 30% E E , ZZeeWWee example:

E%30E%60


Calorimeter technologyCalorimeter technology

To reach goal requires narrow showers To reach goal requires narrow showers and fine segmentation: ECAL: Si+W HCAL: and fine segmentation: ECAL: Si+W HCAL: SS+Scint?SS+Scint?

Iron Tungsten


LC Calorimetry R&D in CanadaLC Calorimetry R&D in Canada

Canadian group is just starting to join Canadian group is just starting to join existing LC calorimeter efforts:existing LC calorimeter efforts: Regina group has experience with SiPM Regina group has experience with SiPM

readout – very attractive option for HCAL readout – very attractive option for HCAL readoutreadout

McGill group to participate in test beam studies McGill group to participate in test beam studies of prototype calorimeter systems (CALICE of prototype calorimeter systems (CALICE collaboration) collaboration)


Bringing the ILC into realityBringing the ILC into reality

An international structure has been set up An international structure has been set up to complete the global design of the ILCto complete the global design of the ILC Leader of the Global Design Effort: Barry BarishLeader of the Global Design Effort: Barry Barish

ILCSC

GlobalDesignEffort

Asia Regional Team

N. American Regional Team

EuropeanRegional Team

Participating Labsand Universities




ILC timescaleILC timescale 2005:2005:

GDE put togetherGDE put together Detector concept groups in formationDetector concept groups in formation

2006:2006: GDE to prepare the ILC Conceptual DesignGDE to prepare the ILC Conceptual Design Detector concept groups to prepare “detector outlines”Detector concept groups to prepare “detector outlines”

2007/8:2007/8: GDE to complete the ILC Technical DesignGDE to complete the ILC Technical Design Detector concepts complete Conceptual DesignsDetector concepts complete Conceptual Designs

2008/9:2008/9: Site selection, government approvals, begin constructionSite selection, government approvals, begin construction Detector collaborations formDetector collaborations form

2015?:2015?: earliest start of experimental programearliest start of experimental program


Next stepsNext steps

Later this summer, a twoLater this summer, a twoweek workshop is beingweek workshop is beingheld at Snowmassheld at Snowmass

finalize baseline accelerator parameters for finalize baseline accelerator parameters for CDRCDR

strong focus on detector concept studiesstrong focus on detector concept studies 450 registered already450 registered already a good opportunity for newcomers to join the a good opportunity for newcomers to join the

efforteffort


Canadian planningCanadian planning

Canadian ILC R&D funded through NSERC Canadian ILC R&D funded through NSERC discovery grantsdiscovery grants eg. 5 grantees on last TPC request (2004)eg. 5 grantees on last TPC request (2004)

Travel to ILC workshops have been Travel to ILC workshops have been supported through IOF grantssupported through IOF grants 14 grantees on last request (2002)14 grantees on last request (2002)

Nucleus of Canadian group is meeting to Nucleus of Canadian group is meeting to plan for future ILC activity:plan for future ILC activity: Montreal / McGill / Carleton / Toronto / Regina / Montreal / McGill / Carleton / Toronto / Regina /

UBC / VictoriaUBC / Victoria Next meeting: June 6, 5:15pm, room: CEME Next meeting: June 6, 5:15pm, room: CEME

12021202(follows PPD session) All are welcome(follows PPD session) All are welcome


SummarySummary The physics case for a Linear Collider is The physics case for a Linear Collider is

very compellingvery compelling The technologies for the machine and the The technologies for the machine and the

experiments are in handexperiments are in hand The international HEP community is solidly The international HEP community is solidly

behind the project and is working together behind the project and is working together to bring it to realityto bring it to reality

To ensure a strong future for particle To ensure a strong future for particle physics in Canada, it is important for us to physics in Canada, it is important for us to participate in this projectparticipate in this project Please join us. For more information see:Please join us. For more information see:

www.linearcollider.org www.linearcollider.cawww.linearcollider.org www.linearcollider.ca

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Dean Karlen University of Victoria & TRIUMF IPP Town Hall Meeting June 4, 2005, TRIUMF.

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