Novel detector concepts for e + e physics Philipp Roloff (CERN) 7 th - - PowerPoint PPT Presentation

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Novel detector concepts for e + e physics Philipp Roloff (CERN) 7 th - - PowerPoint PPT Presentation

May 20, 2023 341 likes •643 views

Novel detector concepts for e + e physics Philipp Roloff (CERN) 7 th Detector Workshop of the Helmholtz Alliance "Physics at the Terascale" The International Linear Collider (ILC) e + e - collisions at high energies linear

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Novel detector concepts for e+e− physics

Philipp Roloff (CERN)

7th Detector Workshop of the Helmholtz Alliance "Physics at the Terascale"

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06/03/2014 Philipp Roloff Detector concepts for e+e− physics 2

The International Linear Collider (ILC)

e+e- collisions at high energies → linear accelerators

  • Based on superconducting RF cavities

(like XFEL → ≈10 % prototype)

  • Gradient: 32 MV/m
  • Energy: 500 GeV, upgradable to 1 TeV
  • Luminosities: few 1034 cm-2s-1
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06/03/2014 Philipp Roloff Detector concepts for e+e− physics 3

The Compact Linear Collider (CLIC)

  • Based on 2-beam acceleration scheme
  • Operated at room temperature
  • Gradient: 100 MV/m
  • Staged construction:

≈375 GeV up to 3 TeV

  • Luminosities: few 1034 cm-2s-1
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06/03/2014 Philipp Roloff Detector concepts for e+e− physics 4

Linear collider physics landscape

Excellent physics program guaranteed at 250/350 GeV:

  • Properties of the Higgs boson
  • Top physics

(including threshold scan)

  • Precision EW and

QCD measurements Discovery potential for New Physics:

  • Direct pair production
  • f new particles

→ mass reach up to √s/2

  • Indirect searches up to scales far

beyond √s (typically up to tens of TeV)

example SUSY scenario from CLIC CDR

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06/03/2014 Philipp Roloff Detector concepts for e+e− physics 5

Higgs physics

At 250/350 GeV: Measurement of σ(HZ) using recoil method → model independent extraction of the Higgs couplings (only possible at lepton collider) At high energy:

  • WW fusion dominates → large samples
  • Extraction of the Higgs self-coupling
  • top Yukawa coupling from ttH events

(maximum around 800 GeV)

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06/03/2014 Philipp Roloff Detector concepts for e+e− physics 6

Physics aims → detector needs (1)

σ ( pT) pT

2

∼2×10

−5GeV −1

Momentum resolution: (e.g. Higgs recoil mass, H → μ+μ-, leptons from BSM processes) H → μ+μ‒ at 3 TeV Higgs recoil mass at 500 GeV

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06/03/2014 Philipp Roloff Detector concepts for e+e− physics 7

Physics aims → detector needs (2)

σ (E) E

Example: W/Z separation (important for many physics processes): 3.5% jet energy resolution → 2.5σ separation

≈ 3 - 4% (ILC) ≈ 5 - 3.5% for jets in the range 50 GeV - 1 TeV (CLIC)

perfect 2% 3% 6% Jet energy resolution:

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06/03/2014 Philipp Roloff Detector concepts for e+e− physics 8

Physics aims → detector needs (3)

σ(d 0)=√a

2+b 2⋅GeV 2/( p 2sin 3θ),a≈5μm ,b≈10−15μ m

Impact parameter resolution:

hit resolution multiple scattering

→ excellent flavour tagging performance Example: branching rations for H → bb/cc/gg (cc and gg not possible at LHC)

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06/03/2014 Philipp Roloff Detector concepts for e+e− physics 9

Particle Flow reconstruction (1)

Composition of a typical jet: Typical jet composition:

  • 60% charged hadrons
  • 30% photons
  • 10% neutral hadrons

Traditional approach:

  • Measure all jet components of jet in

the calorimeters: → 70% of jet measured in HCAL: σE / E ≈ 60% / √E[GeV] → Intrinsically poor HCAL resolution limits jet energy resolution

Ejet = EECAL + EHCAL n π+ γ

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06/03/2014 Philipp Roloff Detector concepts for e+e− physics 10

Particle Flow reconstruction (2)

Particle Flow approach: Try to measure the energies of individual particles

  • charged particles: tracking detectors
  • photons: ECAL

(σE / E ≈ 20% / √E[GeV])

  • neutrals: HCAL

Only 10% of jet energy from HCAL → improved jet energy resolution Particle Flow Calorimetry = Hardware + Software Hardware: resolve energy deposits from different particles → highly granular calorimeters Software: identify energy deposits from each individual particles → sophisticated reconstruction software

Ejet = Etrack + Eγ + En

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06/03/2014 Philipp Roloff Detector concepts for e+e− physics 11

ILC detector concepts

Designed for Particle Flow Calorimetry:

  • high granularity calorimeters (ECAL and HCAL) inside solenoid
  • low mass trackers → reduce interactions / conversions

ILD (International Large Detector):

  • TPC+silicon envelope (radius: 1.8 m)
  • B-field: 3.5 T

SiD (Silicon Detector):

  • Silicon tracking (radius: 1.2 m)
  • B-field: 5 T
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06/03/2014 Philipp Roloff Detector concepts for e+e− physics 12

CLIC detector concepts

Based on ILC designs, adapted and optimised to the CLIC conditions:

  • Denser HCAL in the barrel (Tungsten, 7.5 λ)
  • Redesign of the vertex and forward detectors (backgrounds)
  • Precise timing capabilities of most subdetectors

CLIC_ILD CLIC_SiD

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06/03/2014 Philipp Roloff Detector concepts for e+e− physics 13

Vertex detectors

(CLIC_)SiD: 5 (4) single layers in barrel (endcaps) (CLIC_)ILD: 3 double layers Innermost layer: R ≈ 15 mm (ILC), R ≈ 30 mm (CLIC) Main requirements:

  • very low mass (≈0.2% X0 per layer incl. support and cooling)
  • 3 – 5 μm single hit resolution
  • time slicing with ≈10 ns accuracy for CLIC → see later

example: SiD interaction region

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06/03/2014 Philipp Roloff Detector concepts for e+e− physics 14

Sensor technologies overview

Monolithic 3D-integrated Hybrid

Examples MAPS, FPCCD, DEPFET, HV-CMOS SOI, MIT-LL, Tezzaron, Ziptronix Timepix3/CLICpix Technology Specialised HEP processes, r/o and sensors integrated Customized niche industry processes, high density interconnects btw. tiers Industry standard processes for readout; depleted high-res. planar or 3D sensors Interconnect Not needed SLID, Micro bump bonding, Cu pillars, TSVs Granularity down to 5 μm pixel size ~25 μm pixel size Material budget ~50 μm total thickness achievable ~50 μm sensor + ~50 μm r/o Depletion layer partial partial or full full → large+fast signals Timing Coarse (integrating sensor) Coarse or fast, depending

  • n implementation

Fast sparsified readout, ~ns time slicing possible R&D examples ILC, ALICE, RHIC, Belle II ILC, HL-LHC CLIC, ATLAS-IBL, HL-LHC

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06/03/2014 Philipp Roloff Detector concepts for e+e− physics 15

Tracking systems

SiD: all silicon tracker

  • 5 barrel layers, only axial

measurement

  • 4 disks, stereo layers

→ see talk by Marcel Stanitzki ILD: TPC and silicon trackers

  • one stereo strip layer outside

TPC (SET, ETD)

  • two stereo strips inside TPC (SIT)
  • 220 space points in TPC

→ see talks by Astrid Münnich and Jochen Kaminsky

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06/03/2014 Philipp Roloff Detector concepts for e+e− physics 16

Calorimeters

ECAL: • Absorber: tungsten

  • Active layers: silicon or scintillator

HCAL: • Absorber: iron or tungsten (barrel for CLIC)

  • Active layers: scintillator, different digital

technologies (RPC, GEM, MicroMegas) Comprehensive R&D program for imaging calorimetry within the CALICE collaboration → see talks by Eva Sicking and Frank Simon Forward calorimetry → see talk by Wolfgang Lohmann

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06/03/2014 Philipp Roloff Detector concepts for e+e− physics 17

Background suppression at CLIC

Triggerless readout of full bunch train: t0 of physics event 1.) Identify t0 of physics event in offline event filter

  • Define reconstruction window around t0
  • All hits and tracks in this window are passed to the reconstruction

→ Physics objects with precise pT and cluster time information 2.) Apply cluster-based timing cuts

  • Cuts depend on particle-type, pT and detector region

→ Protects physics objects at high pT

tCluster

During bunch train: 3.2 γγ → hadrons interactions per BX (every 0.5 ns) → pile-up in calorimeters and trackers

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06/03/2014 Philipp Roloff Detector concepts for e+e− physics 18

Time windows and hit resolutions at CLIC

Used in the reconstruction software for CDR simulations:

  • CLIC hardware requirements
  • Achievable in the calorimeters with a

sampling every ≈ 25 ns

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06/03/2014 Philipp Roloff Detector concepts for e+e− physics 19

Impact of the timing cuts

e+e- → tt at 3 TeV with background from γγ → hadrons overlaid 1.2 TeV background in the reconstruction window 100 GeV background after timing cuts

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06/03/2014 Philipp Roloff Detector concepts for e+e− physics 20

Hadronic final states at CLIC

Chargino and neutralino pair production at 3 TeV: 82% 17% Reconstruct W±/Z/h in hadronic decays → four jets and missing energy Precision on the measured gaugino masses (few hundred GeV): 1 - 1.5%

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06/03/2014 Philipp Roloff Detector concepts for e+e− physics 21

If you want to know more...

ILC Technical Design Report (TDR) Volume 4: Detectors arXiv:1306.6329 CLIC Conceptual Design Report (CDR) Volume 2: Physics and Detectors arXiv:1202.5940

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06/03/2014 Philipp Roloff Detector concepts for e+e− physics 22

Summary and conclusions

  • The physics program at linear colliders like the ILC or

CLIC requires detectors with:

  • high momentum resolution
  • excellent jet energy reconstruction
  • precise beauty and charm tagging
  • The (CLIC_)ILD and (CLIC_)SiD detector concepts are

designed to meet these requirements using:

  • low-mass vertex detectors with small pitch
  • high-resolution main trackers
  • imaging calorimeters and particle flow reconstruction
  • Precise timing capabilities are needed in addition to cope with

the experimental conditions at CLIC

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06/03/2014 Philipp Roloff Detector concepts for e+e− physics 23

Backup slides

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06/03/2014 Philipp Roloff Detector concepts for e+e− physics 24

Overview of physics reach

Indicative discovery reach:

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06/03/2014 Philipp Roloff Detector concepts for e+e− physics 25

Selected CLIC parameters

Drive timing requirements for CLIC detector

CLIC at 3 TeV L (cm-2s-1) 5.9 · 1034 Bunch separation 0.5 ns #Bunches / train 312 Train duration 156 ns Train rep. rate 50 Hz Crossing angle 20 mrad Particles / bunch 3.72 · 109 σx/σy (nm) ≈ 45 / 1 σz (μm) 44

Very small beam profile at the interaction point

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06/03/2014 Philipp Roloff Detector concepts for e+e− physics 26

Beam related backgrounds at CLIC

  • e+e- pairs
  • γγ → hadrons

Coherent e+e- pairs: 7 · 108 per BX, very forward Incoherent e+e- pairs: 3 · 105 per BX, rather forward → Detector design issue (high occupancies) γγ → hadrons

  • “Only” 3.2 events per BX at 3 TeV
  • Main background

in calorimeters and trackers → Impact on physics

BX = bunch crossing

detector

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06/03/2014 Philipp Roloff Detector concepts for e+e− physics 27

CLIC project time line

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06/03/2014 Philipp Roloff Detector concepts for e+e− physics 28

Time development in hadronic showers

  • In steel 90% of the energy is recorded within 6 ns (corrected for time-of-flight)
  • In tungsten only 82% of the energy is deposited within 25 ns:

(much larger component of the energy in nuclear fragments) → Energy resolution degrades if not the majority of calorimeter hits is read → Need to integrate over ≈100 ns in the reconstruction, keeping the background level low

Steel-Scint HCAL W-Scint HCAL