1. Mark Thomson University of Cambridge Status of ILD/ CLIC Detector Developments This talk:  ILD LoI  IDAG and post-IDAG  What next?  CLIC issues  Closing Comments

2. LCUK, Cockcroft Institute, 22/09/2009Mark Thomson2 International Large Detector  Based on high granularity particle flow calorimetry confident this will provide necessary jet energy resolution  “Large” central Time Projection Chamber (TPC) proven technology; provides excellent pattern recognition in a dense track environment  Tracking augmented by Si strip/pixels extend tracking coverage + improves precision  A high precision Vertex detector close to IP for best possible heavy flavour tagging  ILD Philosophy

3. LCUK, Cockcroft Institute, 22/09/2009Mark Thomson3 The ILD LoI  The ILD LoI was submitted to IDAG 695 signatories 32 countries from 148 institutions ~40 signatories from 13 UK institutes Very strong EU and Asian participation  Last year saw an intense effort made to optimize detector parameters based on performance  LoI describes baseline design with sub-detector options no premature narrowing down of technological options

4. LCUK, Cockcroft Institute, 22/09/2009Mark Thomson4 Main ILD sub-detector options TPC HCAL  SiW: 5×5 mm 2  ScintW: strips  MAPS: digital ECAL  3 Double Layers  5 Single Layers Vertex Detector HCAL  Steel Scint. Analogue 3×3 cm 2 tiles  Steel RPC (Semi-)digital 1×1 cm 2

5. LCUK, Cockcroft Institute, 22/09/2009Mark Thomson5 ILD Optimisation: Strategy  Scope of Optimisation: Concentrate on global detector parameters: - radius, B-field, HCAL thickness, …  Cost: Large uncertainties in raw materials/sensors For this reason, do not believe optimising performance for given cost is particularly reliable at this stage Whilst conscious of cost, meeting the required performance/ physics goals is the main design criterion One of the strengths of the ILD LoI is the optimisation/justification for the detector: major UK contributions

6. LCUK, Cockcroft Institute, 22/09/2009Mark Thomson6 Optimisation Highlights: Background considerations  Large beam background of low p T electron/positron pairs Radius of pair background envelope is determined by B Determines the minimum inner radius of the vertex detector Potential to impact flavour tagging performance  But radius of pair background envelope scales only as √B  Dependence of inner radius of vertex detector is weaker than √B fixed clearance between background and beam pipe and beam pipe and vertex detector  Consequently 4 T  3 T translates to a ~10 % difference in inner radius of vertex detector – how does this impact flavour tagging

7. LCUK, Cockcroft Institute, 22/09/2009Mark Thomson7 Optimisation Highlights: Flavour Tagging  Compare flavour tagging performance for GLD and LDC based models B = 3.0 T – B = 4.0 T  Conclude: Differences are not large Higher B (smaller inner radius) slightly favoured – but not conclusive due to statistical uncertainties Does not provide a strong argument for higher B field

8. LCUK, Cockcroft Institute, 22/09/2009Mark Thomson8 ILD Optimisation: Summary What did we learn ?  For PFlow, radius is more important than B  Arguments for high B are not strong  For current PFlow algorithm want segmentation ECAL  10×10 mm 2 (5×5 mm 2 preferred) HCAL ~3×3 cm 2 (no obvious advantage in higher granular for analogue HCAL ) (much more detail in LoI) Enabled us to produce a well-motivated ILD reference design I believe we went a long way to understand what makes a good ILC detector In addition… So what did IDAG think…

9. LCUK, Cockcroft Institute, 22/09/2009Mark Thomson9  IDAG Questions  At TILC09, IDAG reviewed ILD LoI  Generally very positive response  Main questions about robustness to background  Prompted a Sashimi/Sushi inspired programme of work…

10. LCUK, Cockcroft Institute, 22/09/2009Mark Thomson10 e.g. Background: TPC  Therefore fill TPC with 150 BXs of background shifted in z  Superimpose on fully-hadronic top-pair events at 500 GeV  Large fraction of hits from low energy electrons/positrons  Form tight helices, “micro-curlers”, along length of TPC  Developed PatRec software to identify and remove “micro-curlers”

11. LCUK, Cockcroft Institute, 22/09/2009Mark Thomson11 Top (p T >1 GeV)Background Raw hits ~8,600 ~265,000 After ~8,500 ~3,000  Effective removal of large fraction of background hits  By eye – clear that this should be no problem for PatRec

12. LCUK, Cockcroft Institute, 22/09/2009Mark Thomson12  Superimpose 150 BXs TPC background on  For 100 events, NO loss in track-finding efficiency observed  Similar story for 3x nominal background  Clear demonstration of the robustness of a TPC operating in ILC beam conditions – probably also true at CLIC (see later)

13. LCUK, Cockcroft Institute, 22/09/2009Mark Thomson13 IDAG Report : ILD Validated “The ILD detector design concept appears already to confront the physics of the ILC in a fairly complete fashion. At the LOI stage the progress of the Collaboration in realizing their detector concept is impressive and the path is clear for ILD to make continued progress. The strength of the ILD group is sufficient for the tasks ahead in R&D, simulation and engineering the ILD concept toward a more completely realized detector.” “The ILD Collaboration has presented a LOI which documents the impressive quantity and quality of work performed. A particular strength of the LOI is the very extensive R&D effort made in test beams with full-size prototypes of the calorimeter having been constructed and operated at DESY, CERN and Fermilab.” “The ILD efforts on simulating the physics benchmark processes have been impressive. Significant progress has been made even since the LoI itself in response to the questions posed by IDAG.”  ILD “Validated” with very positive comments from IDAG

14. LCUK, Cockcroft Institute, 22/09/2009Mark Thomson14  What now for ILD ?  After brief post-LoI period of recovery, beginning to plan for the next steps (focus of Albuquerque ILD meeting).  Main issues:  Continued detector R&D towards prototypes, e.g. CALICE UK disengagement from the core of ILC R&D activities a a major concern  Full evaluation of potential of detector options UK needs to make sure MAPs is part of this  Further define engineering aspects of concept  Better understand background and safety factors significant simulation/software effort  Evaluate ILD performance at 1 TeV and beyond… already started in LoI

15. LCUK, Cockcroft Institute, 22/09/2009Mark Thomson15  CLIC Detector Issues  CLIC aiming for a detector CDR in 2010, including evaluation of physics performance  this is a lot of work ! Took ILC detector concepts many years to get to this point  CERN do not have the resources to do this from scratch  aim to minimally modify ILC concepts (ILD and SiD) to perform studies  UK playing major role in links between ILC concepts and CLIC (Marcel for SiD, myself for ILD)  at very least, possible useful strategic connection  CERN has now joined CALICE and LCTPC Many interesting questions, e.g.: Does particle flow work at CLIC energies? Can a TPC work in the CLIC background environment?

16. LCUK, Cockcroft Institute, 22/09/2009Mark Thomson16 125 GeV Z250 GeV Z500 GeV Z1 TeV Z Particle flow reco. might help here PFA at CLIC Energies  On-shell W/Z decay topology depends on energy: LEP ILCCLIC  PandoraPFA + ILD + performance studied for:  A few comments:  Particle multiplicity does not change  Boost means higher particle density  PFA could be better for “mono-jet” mass resolution More confusion

17. LCUK, Cockcroft Institute, 22/09/2009Mark Thomson17  Studied W/Z separation using ILD + samples of ILC-like energies CLIC-like energies Clear separation There is separation, although less clear vs.  PFA will work (to some extent) at CLIC  Likely to be at least competitive with traditional calorimetry  Full reach of PFA at CLIC needs real algorithm development  Looks promising…

18. LCUK, Cockcroft Institute, 22/09/2009Mark Thomson18 Background at CLIC  CLIC bunch structure very different to ILC  Bunch-trains of 150 bunches separated by 0.5 ns  Single BX tagging seems very unlikely  Some sub-detectors may have to integrate over entire bunch-train  If so “two photon” background very large  Potentially makes CLIC a very different machine from ILC this needs to be understood PRELIMINARY: stau pair + 75 BXs of background

19. LCUK, Cockcroft Institute, 22/09/2009Mark Thomson19 Can a TPC work at CLIC?  “by eye” tracks still clearly resolved Conclude ILD-like detector, not ruled out for CLIC  Detailed simulation studies needed…

20. LCUK, Cockcroft Institute, 22/09/2009Mark Thomson20  Final Comments  ILD has (I believe) been demonstrated to be a strong candidate for a detector at the ILC operating in the energy range 0.5-1.0 TeV  ILD has broad international support and builds on a strong R&D programme: CALICE, LCTPC, SiLC  The UK made a number of central contributions to the ILD LoI  Need to maintain UK visibility in ILD – e.g. attendance at ILD meetings (next one in Paris: either December or January)  Existing UK CALICE/LCFI effort dissolving fast  Disconnect between UK and major R&D collaborations is a major concern  If the ILC were to move ahead rapidly, the UK is not ideally positioned to make major contributions to the ILC detector(s) The good… The not so good… Need to try and re-engage with major international ILC detector R&D efforts Opinion