CERN R&D on Linear Collider Detectors. Lucie Linssen CERN

Transcription

1 CERN R&D on Linear Collider Detectors Lucie Linssen CERN 1

2 Outline Outline: Introduction CLIC physics Detector issues Comparison between ILC and CLIC Linear Collider Detector R&D plans Outlook 2

3 Introduction 3

4 ILC and CLIC in a few words linear collider, producing e + e - collisions CLIC ILC 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 Based on superconducting RF cavities Gradient 32 MV/m Energy: 500 GeV, upgradeable to 1 TeV (~200 GeV ZZ is also considered) Detector studies focus mostly on 500 GeV Luminosities: few cm -2 s -1 4

5 ILC: Harry Weerts 5

6 LC technology collaborations Large international collaborations for Linear Collider detector technology studies: CALICE Fine grained calorimetry, based on particle flow analysis LC-TPC Time projection chmber based on MPGD readout SILC Silicon-based tracking technologies FCAL Very forward region: background studies and calorimetry EUDET EU-funded FP6 project on LC detector technologies So far these technology collaborations have concentrated on ILC 6

7 ILC experiment concepts SiD ILD 4th 3 LoI documents submitted 31/3/2009 7

8 Linear Collider Detector CERN Motivation: Substantial CLIC accelerator effort towards Conceptual Design Report (CDR) for end 2010 Include CDR chapters on the CLIC physics potential, CLIC detector concepts and their related technological issues CLIC detector concept will be very similar to ILC concepts A few challenging differences: Higher energy Increased background conditions Difference in time structure Profit from many years of investment in ILC e + e - physics/detector simulations, hardware R&D and detector concepts LCD@CERN: Working together with the ILC detector concepts and with the linear collider detector technology collaborations to study modifications to the ILC concepts for CLIC energies and beam conditions. 8

9 LCD collaboration with ILC Linear Collider Detector web site: has joined existing linear collider groups: ILC detector concepts (LCD members signed LoI s) ILD SiD 4 th concept Technology collaborations (formal agreements / letters) LC-TPC (TPC development) CALICE (calorimetrybased on Particle Flow Analysis) FCAL (very forward region studies) European project (CERN is member) EUDET 9

10 CLIC physics a few examples 10

11 General Physics Context New physics expected in TeV energy range Higgs, Supersymmetry, extra dimensions,? LHC will indicate what physics, and at which energy scale ( is 500 GeV enough or need for multi TeV? ) Even if multi-tev is final goal, most likely CLIC would run over a range of energies (e.g TeV) 11

12 Heavy mass SUSY particles e.g. e + e - H 0 A 0 production e + e - H 0 A 0 bƃbƃ m H,A 1 TeV Yellow dots mostly from γγ 12

13 e + e - H 0 A 0 at 3 TeV H 0 A 0 bƃbƃ 3 ab -1 Black without γγ background Blue with γγ background + 25 ns time stamping 13

14 Example of CLIC SUSY particle Search Dilepton spectrum in neutralino decay Reach in parameter space + 2% Dimuon mass 14

15 New resonances at CLIC New Resonances at CLIC e + e Z' µ + µ Radiative decay Energy scan E cm = 1 TeV M Z = 750 GeV +ISR +BStr m µµ

16 Universal Extra Dimensions at CLIC Extra Dimensions and SUSY have rather similar signatures at LHC. Clean final states and control of CM energy at CLIC allows separation. Example: pair produced KK muons and SUSY smuons: produced reconstructed UED SUSY Angular distribution of muon M. Battaglia, AK Datta, A droeck, K Kong, K Matchev 16

17 Extra Dimensions Graviton production at CLIC In UED theories, TeV-scale Graviton resonances are predicted, decaying into γγ, gg or ffbar pairs. Cross sections are large. 17

18 Extra Dimensions Graviton production at CLIC Example m G1 = 1.2 TeV, G 1 two jets (qq or gg ) Sequen.al decay G 3 G 1 G 1 4 jets Dijet mass 18

19 CLIC detector issues, and comparison with ILC 19

20 CLIC detector issues 3 main differences with ILC: Energy 500 GeV => 3 TeV More severe background conditions Due to higher energy Due to smaller beam sizes 3TeV e + e - W + W - qqqq Time structure of the accelerator 20

21 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 Consequences for CLIC detector: Need for detection layers with time-stamping Innermost tracker layer with ~ns resolution or. all-detector time stamping at the 10 ns level Readout/DAQ electronics will be different from ILC Power pulsing has to work at 50 Hz instead of 5 Hz 21

22 Beam-induced background Background sources: CLIC and ILC similar Due to the higher beam energy and small bunch sizes they are significantly more severe at CLIC. Main backgrounds: CLIC 3TeV beamstrahlung ΔE/E = 29% (10 ILC value ) Coherent pairs ( per bunch crossing) <= disappear in beam pipe Incoherent pairs ( per bunch crossing) <= suppressed by strong solenoid-field γγ interactions => hadrons (2.7 hadron events per bunch crossing) Muon background from upstream linac More difficult to stop due to higher CLIC energy (active muon shield) 22

23 CLIC centre-of-mass energy spectrum Due to beamstrahlung: At 3 TeV only 1/3 of the luminosity is in the top 1% centre-of-mass energy bin Many events with large forward or backward boost 23

24 Extrapolation ILC = > CLIC <= 10% beam crossing in ILD detector at 500 GeV Adrian Vogel, DESY For full LDC detector simulation at 3 TeV Simulation of e + e - pairs from beamstrahlung Conclusion of the comparison: ILC, use 100 BX (1/20 bunch train) CLIC, use full bunch train (312 BX) CLIC VTX: O(10) times more background CLIC TPC: O(30) times more background LDC 3 TeV, with forward mask 24

25 Vertex and Tracking issues: CLIC Tracking Due to beam-induced background and short time between bunches: Inner radius of Vertex Detector has to become larger (~25 mm) High occupancy in the inner regions Narrow jets at high energy 2-track separation is an issue for the tracker/vertex detector Track length may have to increase (fan-out of particles within jet) 3TeV e + e - t t bar 25

26 distance of leading particles in jets Jean-Jacques Blaising, LAPP 26

27 CLIC Calorimetry Higher energy => need deeper HCAL ( 8λ i ) Cannot increase coil radius too much => need heavy absorber Choice of suitable HCAL material Choice of Calorimeter technology (PFA or Dual readout) Method and Engineering Based on Particle Flow Algorithm difficult, but conventional Highly segmented (~25 mm 2 ) ECAL Limited in energy-range Segmented HCAL to a few hundred GeV Based on Dual (Triple) readout Sampling calorimeter Based on fibre readout Fully active calorimeter (EM part) Method and Engineering difficult and non-proven Crystal-based Not limited in energy range 27 27

28 Jet multiplicities 3TeV e + e - W + W - qqqq 28

29 Energy of single hadrons in jets ttbar events at 3 TeV Jean-Jacques Blaising, LAPP 29

30 Linear Collider CERN R&D plans 30

31 LCD project plans In several aspects the CLIC detector will be more challenging than ILC case Most of the R&D currently carried out for the ILC is most relevant for CLIC. Besides extensive simulation studies and software development for the CLIC detector studies, CLIC-specific hardware and engineering development is required in a number of areas. Current scenario: Conceptual Design Report: end 2010 Technical Design Report

32 Hardware/engineering R&D Hardware/engineering R&D needed beyond present ILC developments: Time stamping Most challenging in inner tracker/vertex region Trade-off between pixel size, amount of material and timing resolution Power pulsing and other electronics developments In view of the CLIC time structure Hadron calorimetry Dense absorbers to limit radial size (e.g. tungsten) PFA studies at high energy Alternative techniques, like dual readout Solenoid coil Reinforced conductor (building on CMS/ATLAS experience) Large high-field solenoid concept Precise stability/alignment studies In view of sub-nm precision required for FF quadrupoles Overall engineering design and integration 32

33 Conclusions Development of a future linear collider at the TeV scale has a high priority within the European strategy for particle physics It is timely to complement the large investment in the CLIC accelerator technology with an in-depth assessment of the detector aspects and it physics potential. With the aim of producing a common CLIC CDR, end 2010 The Linear Collider Detector project at CERN integrates well into the existing world-wide LC physics/detector studies and profits from many years of investment in ILC physics/detector simulations, hardware R&D and detector concepts Work at CERN will concentrate on critical items for CLIC. No duplication of work. Heavy Higgs decay at 3 TeV This project is an integrated part of the ILC-CLIC collaboration and agreement to work together towards a well-founded assessment of all essential accelerator and detector issues (physics potential, technology, time-line, cost) in preparation for future strategic decisions. 33

34 SPARE SLIDES 34

35 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? 35

36 CLIC parameters 36

37 Alternative to PFA calorimetry R&D on dual/triple readout calorimetry Basic principle: Measure EM shower component separately Measure HAD shower component separately Measure Slow Neutron component separately Dual Triple EM-part=> electrons => highly relativistic => Cerenkov light emission HAD-part=> less relativistic => Scintillation signal Slow neutrons => late fraction of the Scintillation signal Requires broader collaboration on materials + concept 37

38 Precise alignment/stability Precise alignment studies/technologies Beam focusing stability!! How to link left-arm and right-arm? Lumical =>measurement using Bhabha scattering Alignment of last quadrupoles at m ILC alignment requirements => <4 µm (x,y), <100 µm (z) CLIC requirement is be more severe Lucie Linssen, Daniel SPC, Schulte 15/6/2009 CLIC08. Leszek Zawiejski, FCAL collab. 38

39 SiD Forward Region LumiCal 20 layers of 2.5 mm W + 10 layers of 5.0 mm W ECAL BeamCal 50 layers of 2.5 mm W Beampipe 3cm-thick Tungsten Mask +/- 94 mrad (detector) 13cm-thick BoratedPoly +101 mrad, -87mrad (ext. line) Centered on the outgoing beam line 39

40 (Foreseen budget allows for simulation studies and several hardware R&D activities) 40

41 Lucie Linssen, SPC, 41 15/6/2009