1. Linear Collider Detector (LCD) project overview
Outline:
Introduction to CLIC accelerator
CLIC physics potential
Detector requirements, ILC and CLIC
Current activities and R&D plan
Summary
Lucie Linssen
PH senior staff meeting, March 4th 2010
Lucie Linssen, 3/3/2010

2. General LCD Context
The LHC will determine the future of high-energy physics. The linear collider is one of the best options to complement and extend the LHC programme
New physics expected in TeV energy range
E.g. motivated by particle astrophysics (dark matter)
Higgs, Supersymmetry, extra dimensions, …?
LHC will indicate what physics, and at which energy scale:
Is 500 GeV enough (ILC)
Is there a need for multi TeV? (CLIC)
The CERN “Linear Collider Detector” project addresses both ILC and CLIC, though current focus is on the preparation of the CLIC physics/detector CDR, due for April 2011
Lucie Linssen, 3/3/2010

3. ILC and CLIC in a few words…
linear collider, producing e+e- collisions
CLIC
ILC
Based on superconducting RF cavities
Gradient 32 MV/m
Energy: 500 GeV, upgradeable to 1 TeV (lower energies also considered)
Detector studies focus mostly on 500 GeV
Based on 2-beam acceleration scheme
Gradient 100 MV/m
Energy: 3 TeV, though will probably start at lower energy (~0.5 TeV)
Detector study focuses on 3 TeV
Luminosities: few 1034 cm-2s-1
Lucie Linssen, 3/3/2010

4. The CLIC Two Beam Scheme
Drive Beam supplies RF power
12 GHz bunch structure
low energy (2.4 GeV MeV)
high current (100A)
Main beam for physics
high energy (9 GeV – 1.5 TeV)
current 1.2 A
No individual RF power sources
Lucie Linssen, 3/3/2010

5. The full CLIC scheme Not to scale!
Lucie Linssen, 3/3/2010

6. CLIC physics up to 3 TeV What can CLIC provide in the 0.5-3 TeV range?
In a nutshell…
Higgs physics:
Complete study of the light standard-model Higgs boson, including rare decay modes (rates factor ~5 higher at 3 TeV than at 500 GeV)
Higgs coupling to leptons
Study of triple Higgs coupling using double Higgs production
Study of heavy Higgs bosons (supersymmetry models)
Supersymmetry:
Extensive reach to measure SUSY particles
And in addition:
Probe for theories of extra dimensions
New heavy gauge bosons (e.g. Z’)
Excited quarks or leptons
Lucie Linssen, 3/3/2010

7. (S)LHC, ILC, CLIC reach Gian Giudice CLIC09
Lucie Linssen, 3/3/2010
Gian Giudice CLIC09

8. ILC and CLIC detector studies
In several aspects the CLIC detector will be more challenging than ILC case, due to:
Energy 500 GeV => 3 TeV
More severe background conditions
Due to higher energy
Due to smaller beam sizes
Time structure of the accelerator
Detector studies and R&D for the ILC are most relevant for CLIC.
Many years of investment in ILC e+e- physics/detector simulations, hardware R&D and detector concepts. No need to duplicate work.
Therefore we have joined several Linear Collider (ILC) collaborations:
ILD concept, SiD concept, CALICE, FCAL, LC-TPC + EU projects (EUDET/AIDA).
Lucie Linssen, 3/3/2010

9. ILC=> CLIC detector requirements
Lucie Linssen, 3/3/2010

10. Validated ILC concepts
CLIC detector concepts will be based on SiD and ILD.
Modified to meet CLIC requirements
Lucie Linssen, 3/3/2010

11. CLIC and ILC time structure CLIC time structure
Train repetition rate 50 Hz
CLIC
CLIC: 1 train = 312 bunches 0.5 ns apart 50 Hz
ILC: 1 train = 2820 bunches 308 ns apart 5 Hz
Lucie Linssen, 3/3/2010

12. Beam-induced background
Main backgrounds:
CLIC 3TeV beamstrahlung ΔE/E = 29% (10×ILCvalue)
Coherent pairs (3.8×108 per bunch crossing) <= disappear in beam pipe
Incoherent pairs (3.0×105 per bunch crossing) <= suppressed by strong solenoid-field
γγ interactions => hadrons (3.3 hadron events per bunch crossing)
In addition: Muon background from upstream linac
Lucie Linssen, 3/3/2010

13. Beam-induced background and time–stamping
γγ=> hadron events dump 7.5 TeV in the detector for each bunch train
For example: ±10 degrees jet cone and 10 nsec time stamping:
=> 2 GeV in the cone (barrel) and 20 GeV in the cone (end cap)
Lucie Linssen, 3/3/2010
Jean-Jacques Blaising, LAPP

14. At high energy physics goes in forward direction
Background is also principally in forward direction.
Detector optimisation needs special attention here.
Lucie Linssen, 3/3/2010
Marcel Vos, IFIC

15. CLIC tracking/calorimetry issues
Due to beam-induced background and short time between bunches:
Inner radius of Vertex Detector has to become larger (~30 mm)
High occupancy in the inner regions
Time-stamping is a must for almost all detectors
Narrow jets at high energy
Will Particle Flow Analysis still work at required precision?
Calorimeter has to measure high-energy particles (leakage)
3TeV e+e-  t tbar
Lucie Linssen, 3/3/2010

16. Jet Energy Resolution and PFA
Is an ILD-sized detector based on PFA suitable for CLIC ?
Defined modified ILD+ model:
B = 4.0 T (ILD = 3.5 T)
HCAL = 8 ΛI (ILD = 6 ΛI)
Jet energy resolution
PFA
EJET
sE/E = a/√Ejj |cosq|<0.7
sE/Ej
45 GeV
25.2 %
3.7 %
100 GeV
28.7 %
2.9 %
180 GeV
37.5 %
2.8 %
250 GeV
44.7 %
375 GeV
71.7 %
3.2 %
500 GeV
78.0 %
3.5 %
Mark Thomson
Cambridge
Meet “LC jet energy resolution goal [~3.5%]” for 500 GeV ! jets
Lucie Linssen, 3/3/2010

17. Tungsten HCAL prototype
Motivation:
To limit longitudinal leakage CLIC HCAL needs ~7Λi
A deeper HCAL pushes the coil/yoke to larger radius (would give a significant cost and risk increase and for the coil/yoke)
A tungsten HCAL is more compact than Fe-based HCAL, while resolutions are similar (increased cost of tungsten barrel HCAL compensates gain in coil cost)
Prototype tungsten HCAL: check simulation in test beam
Fe and W based HCAL resolutions
Angela Lucaci-Timoce DESY)
Lucie Linssen, 3/3/2010

18. Final focus stability
Final focus quadrupoles inside experiment, L* = ~3.5 m
Beam focusing stability required at sub-nm level !!
Daniel Schulte CLIC08.
Lucie Linssen, 3/3/2010

19. Engineering issues
Current engineering studies mostly concentrate on the critical issue of providing a stable environment for the forward focus quadrupole QD0.
Measurements in CMS and several (LHC-) underground locations have guided ideas about how to suspend QD0 within the experiment volume. These ideas are currently being worked out.
see MDI talk 27/1 Alain Herve
experiment
tunnel
Forward detector region with final focus elements
Alain Herve (ETHZ), Hubert Gerwig (CERN)
Lucie Linssen, 3/3/2010

20. Current LCD activities
Current activities concentrate on preparation for CDR
Mostly simulation studies:
Demonstrate that CLIC physics potential can be extracted from detector
Propose ILD-type and SiD-type detectors that can do the job
Concentrate on critical issues
Determine required sub-detector performances to see the physics
Redesign of the very forward region
Take engineering aspects, cost etc into account
Preparing a targeted
hardware R&D plan
Lucie Linssen, 3/3/2010
Andre Sailer (CERN)

21. Hardware/engineering R&D
LCD hardware/engineering R&D (needed beyond ILC developments):
Time stamping
Most challenging in vertex detector: trade-off between pixel size, amount of material and timing resolution
Power pulsing
In view of the 50 Hz CLIC time structure => allows for low-mass detectors
Hadron calorimetry ✪
Tungsten-based HCAL (PFA calo, within CALICE)
Solenoid coil
Large high-field solenoid concept
Reinforced conductor (building on CMS/ATLAS experience)
Overall engineering design and integration studies
For heavier calorimeter, larger overall CLIC detector size etc.
In view of sub-nm precision required for FF quadrupoles
In addition: TPC electronics development (Timepix-2, S-ALTRO✪)
✪ also in AIDA EU proposal
Lucie Linssen, 3/3/2010

22. Core software development
Ongoing developments with involvement of PH-SFT and PH-LCD:
Use of enhanced ROOT functionalities in ILC software (mostly in collaboration with DESY)
Improved geometry toolkit in ILD code (CERN+DESY)✪
Improvements of hadronisation process descriptions in Geant4 (collaboration between CERN/Geant4 and CALICE)
Grid processing and file catalog: we receive support from LHCb to duplicate their DIRAC system.
Participation in Pandora-PFA code development (Cambridge+CERN)✪
✪ also in AIDA EU proposal
Lucie Linssen, 3/3/2010

23. Summary Welcome to join
CLIC has a large physics potential, complementary to LHC
CLIC physics/detector studies in close collaboration with ILC
Growing community both inside and outside CERN
Software tools in place for adapted ILD and SiD detector models
Work currently focuses on CLIC physics/detector CDR (April 2011)
LCD hardware R&D is starting
Welcome to join
Lucie Linssen, 3/3/2010

24. Thank you! CLIC_ILD detector CLIC_SiD detector
Lucie Linssen, 3/3/2010

25. Spare Slides
Lucie Linssen, 3/3/2010

26. CLIC parameters
Lucie Linssen, 3/3/2010

27. Tentative long-term CLIC scenario
Technology evaluation and Physics assessment based on LHC results
for a possible decision on Linear Collider with staged construction starting with the lowest energy required by Physics
Conceptual
Design
Report (CDR)
Technical
Design
Report (TDR)
Project
approval ?
First
Beam?
Lucie Linssen, 3/3/2010

28. Example:…. light SM-like Higgs
The cross-section at ~3TeV is very large  access to very rare decays (BR~10-4). Measure Higgs couplings to leptons, for instance with 0.5 ab-1, we expect ~70 H+- decays for Mh=120 GeV/c2, and measure the couplings with ~4% precision.
1/s
log(s)
Lucie Linssen, 3/3/2010
Frederic Teubert

29. Example: heavy mass SUSY particles
e.g. e+e- → H0A0 production
e+e- → H0A0 →bƃbƃ
s-channel vs t-channel cross sections √S
mH,A ≈ 1 TeV
Yellow dots mostly from gg
Marco Battaglia
Lucie Linssen, 3/3/2010

30. Example: SUSY mass measurement
Gian Giudice CLIC09
Lucie Linssen, 3/3/2010

31. Mark Thomson
Lucie Linssen, 3/3/2010

32. ILD concept adapted to CLIC
Changes to the ILD detector:
20 mrad crossing angle
Vertex Detector to ~30 mm inner radius, due to Beam-Beam Background
HCAL barrel with 77 layers of 1 cm tungsten
HCAL endcap with 70 layers of 2 cm steel plates
Forward (FCAL) region adaptations
Fully implemented in Mokka/Marlin
Andre Sailer
Lucie Linssen, 3/3/2010

33. Time stamping requirements (2)
Simulation example of heavy Higgs doublet H0A0 at ~1.1 TeV mass (supersymmetry K’ point) e+e-  H0A0  bbbb Signal + full standard model background + γγ=>hadron background CLIC-ILD detector: Mokka+Marlin simulation, reconstruction + kinematic fit.
Zero bunch crossings
MA mass resol. 3.8 GeV
20 bunch crossings
MA mass resol. 5.6 GeV
40 bunch crossings
MA mass resol. 8.2 GeV
Lucie Linssen, 3/3/2010
Marco Battaglia