Conclusions and Outlook

1
Conclusions and Outlook

• Ambleside, September 2006
• F. Richard LAL/Orsay

2
What did you learn?

• This school has given you a complete panorama
  about ILC 
• A description of how a GDE has been set and what
  is the international context of ILC
• What are the resources and the problems to build
  this Machine
• What are the proposed Detectors and which efforts
  remain to reach completion
• What are the interface issues between these
  detectors and ILC (P, dL/dE, E, IR)
• And, most important, for which physics do we
  build ILC
• Also, the context in which we are heading towards
  such a decision the nearby start of LHC and
  eventually the role of CLIC in Europe

3
What I intend to do now

• Here I would like to try some kind of personal
  synthesis of these points and project on the near
  future
• Also I wish to do this taking into account
  your legitimate preoccupations
• Where do I (that is you) stand in this as a young
  physicist?
• Which opportunities are open, when and where to
  go?
• At least, I will try

4
First question Why is ILC so special ?

• So far CERN, DESY, FNAL, KeK, SLAC have
  designed and built more or less independently
  their large colliders with an a posteriori
  international participation
• Advantages were it started from an existing lab,
  did not require a lengthy and complicated
  international process for funding and managing
  the new accelerator

5
What has changed

• What are the reasons to change with this well
  established procedure which worked up to LHC?
• - SSC, which went up to construction, was
  done on a national basis WITHOUT using an
  existing site which resulted in a very serious
  over cost and finally a failure
• - TESLA, the cold technology project,
  organized around DESY with European
  participation, went up to a TDR with costing
  (result of 10 years of RD reduction of cost
  20)
• In parallel to TESLA, KeK and SLAC were
  developing a warm technology requiring extra
  money and manpower for a competitive RD

6
The new line

• The German government has decided not to
  proceed nationally and at this moment not to
  propose a German site for TESLA
• Start a project at the worldwide level
• Put in common all the money and efforts after
  choosing a common technology
• How does this ILC scenario compares with LHC ?

7
The LHC case

• LHC, a purely European initiative, went
  through a very lengthy procedure
• 1981 Lausanne ECFA workshop LHC in LEP tunnel
• 1986 La-Thuile workshop (LHC/CLIC) fist design
• 1988 Feasibility of High Luminosity expts at
  LHC Geneva meeting
• 1990 Aachen meeting main lines are delineated
• 1992 Detector collaborations were formed
• Comment we are not there but detectors are
  simpler?
• 1997 Civil engineering starts
• -gt For such machines, timing is therefore of
  major concern

8
The timing issue (how to survive waiting for a
collider?)

• At LHC
• The vast majority of LHC physicists were
  participating to other experiments (LEP,
  Tevatron)
• The dedicated LHC physicists and engineers had
  interest in instrumentation i.e. participated to
  RD collaboration, took data on test beams,
  prepared the LHC hardware and software etc
• Similar things are happening with ILC
• The first phase with TESLA was largely driven by
  physicists of LEP12
• At present an active RD, with test beams has
  started all around the world with important
  prototyping with physicists and engineers
  involved at Tevatron, HERA and even LHC
• In addition a new type of effort has started with
  HEP physicist getting involved in activities
  called Machine Detector Interface

9
Where are the resources coming from?

• Large support in UK, France, Germany and now
  Spain, Italy (started with TESLA)
• European Money has helped for hardware Postdoc
  positions
• 3 European contracts CARE (technology) EUROTEV
  (Design) EUDET (Detector RD)
• 100 success !
• The RD panel for detectors shows this
• Has triggered extra money in the 2 other
  regions

10
The Physics Program of ILC

• Main motivations in few words
• The LEP/SLC Tevatron legacy Higgs mass
  prediction mH 85 GeV mHlt166 GeV
• Comment has LEP2 missed the Higgs? This
  question will be irrelevant with ILC, not with
  LHC
• Theoretical puzzles and conjectures Hierarchy
  issue, GUT argument, cosmological puzzles

11
Caveat

• SLC-LEP1 discrepancy
• GigaZ with e polarization will decrease
• errors by gt10
• This effect is natural in xtra dimensions
• Different behavior of the heavy quarks
• It should manifest itself in top couplings
• NB ILC has the final word in RS up to
• 20 TeV scale

12
Therefore

• Experiment cries out for a light Higgs. ILC is
  THE ideal machine to tackle this theme
• Moreover PM have shown their power for predicting
  new particles. ILC can do much better in
  particular because it has electron polarization
• Not enough claim the sceptics (why?)
• Then comes the theoretical arguments which are
  based on indirect (hierarchy pb, unification of
  forces) semi-direct (DM, g-2) evidence for SUSY

13
SUSY?

• In favour of SUSY
• MSSM passes all precision measurements
• mH 100 GeV
• Grand Unification of the 3 forces
• (g-2)µ deviation at gt 3 sd which is possible with
  SUSY loops (without affecting PM)
• A nice candidate for DM

14
SUSY?

• Against SUSY
• Should have been seen at LEP2 in a constrained
  scheme without F.T.
• With additional phases, should have been seen in
  EDM e,n and/or in B-physics unless
• there are no phases ?
• Hierachy of fermion masses not understood
• mt/me106 not to mention neutrinos FCNC

15
What else?

• Alternate schemes are considered which may not be
  exclusive of SUSY
• - extra dimensions like RS
• - composite Higgs like TC
• In these theories one predicts new bosons and new
  fermions and one of the main issue is to pass the
  PM from LEP/SLD !
• This means that ILC will ultimately test these
  ideas, beyond LHC

16
A Z scenario
LHC - up to 5 TeV direct observation - up
to 2 TeV identif. LC - discriminate between
models up to ? 5 TeV - predict MZ with a
relative accuracy lt (MZ/10TeV)² lt 25 at 5 TeV
XY1
E6 Little Higgs
(1 TeV 1 ab-1)
17
My conclusions

• Almost independently what happens at LHC, ILC has
  an very strong case with Higgs physics and PM
• This great program could still be extended if new
  physics, like SUSY, falls within the TeV range
• What happens at LHC may of course have an impact
  on the roadmap of ILC (maximum energy, need for
  GigaZ), but should not determine the issue

18
Devils advocate

• WAIT FOR CLIC WHICH CAN COVER ANY SCENARIO (?)
• NB SUSY can survive up to masses not accessible
  at LHC and still compatible with DM and GUT (but
  inconsistent with g-2) e.g. Wino LSP 2 TeV
• gt 4 TeV machine would be needed. Quite a big jump
  in technology
• Note that this type of argument could apply to
  any project, in particular LHC, which could be
  differed on the basis of potential progress on
  dipole fields etc
• Contrary to many machines decided in the past,
  sometimes very costly, ILC is designed with well
  defined objectives
• Nevertheless

19
Is CLIC almost ready to be built ?

• Not easy to answer this question and it would be
  unfair to do it here without a contradictory
  debate
• It is/seems fair to say that
• So far the RD on CLIC has been a second priority
  for CERN
• For this reason, this technology could not be
  retained in the ILC selection
• It is unrealistic to imagine that CLIC could jump
  directly from 100 GeV (SLC) to a few TeV and
  therefore an intermediate machine is needed Time
  scale ?
• Without even specifying the technology, going
  beyond 1 TeV with an appropriate luminosity
  requires improvement on emittance not yet
  demonstrated
• Having recalled these debates, it is essential
  that the CLIC RD be pursued to insure a future
  after LHC/ILC

20
When?

• 2010 to take a decision with a fully costed TDR
  based on realistic site(s)
• Construction of the Machine starts at Tc
• Tc cannot be gtgt 2010
• There is a window of opportunity for this
  machine and this technology (as for any
  technology)

21
When for the Detector?

• Common prejudice the detector is trivial!
• Lets take a LEP/SLC scaled up by 1.5 in R
  (dp/p²1/BR²) detector et voila
• Lets constitute a international collaboration at
  Tc and build it
• Wrong!
• Probably much less challenging then e.g.
  ATLAS but
• Final states are much more complex at ILC 6-8
  jets
• Any inefficiency in jet reconstruction translates
  into a severe overall effect e.g. ZHH
• LEP PFLOW performance was only optimal in the
  barrel region
• This performance can be improved by 2

22
Detector

• What is needed to improve on these figures ?
• 1 high granularity at the level of tracking and
  calorimetry
• 2 high density of the calorimetry
• Both HCAL and ECAL inside the coil
• 1 and 2 have improved dramatically with
  miniaturization of microelectronics

23
Exemple of ECAL

• Good segmentation (60 M Si pads 0.5x0.5 cm²)
  with integrated electronics
• Low consumption pulsing

24
It is happening right now!

• Data taken at DESY, CERN in test beams
• Real HEP experiments with gt10000 channels
• e.g. CALICE collaboration has taken 20M triggers
  this month in a CERN test beam with ECAL and HCAL

25
It is happening right now!
Tile- SiPM HCAL
Si-W ECAL
p 30 GeV
26
What about MDI ?

• Not covered here due to lack of time
• Different situation /LEP intrincate
  Detector/Machine aspects
• Immense effort involving HEP physicists also with
  test beams (SLAC, KeK)
• Forward region issues
• L to 10-4, dL /dE for threshold scans,
  polarisation, etc..

27
CONCLUSIONS

• ILC effort has converged into an intense phase of
  RD both for the Machine and the Detector
  exciting to join now !
• Physics goals are clear and convincing
• ILC costing is the critical part and we will know
  soon
• If this step is passed then there should be a
  fast evolution towards the choice of 2 detectors
  with well structured collaborations
• JOIN NOW !