clic detector and physics status

CLIC DETECTOR AND PHYSICS STATUS

Ivanka Božović Jelisavčić

Vinca Institute of Nuclear Sciences, Belgrade

[on behalf of the CLIC Detector & Physics Collaboration]

OVERVIEW

Reminder – CLIC environment and detector implications

Detector optimization studies Hardware R&D Software development

Status of the ongoing Higgs physics analyses

About CLICdp Conclusions

2 I. Bozovic Jelisavcic CLIC Detector & Physics Status AWLC 2014, Fermilab, 12-16 May 2014

REMINDER - CLIC MACHINE ENVIRONMENT

CLIC 0.5 TeV CLIC 3 TeV

L [cm-2s-1] 2.3×1034 5.9×1034

BX/train 354 312

BX separ. 0.5 ns 0.5 ns

Rep. rate 50 Hz 50 Hz

L/BX [cm-2] 1.1×1030 3.8×1030

σx/σy 202/2 nm 40/1 nm

(X)/BX 0.2 3.2


o Small beam profile at IPo Bunch population

~3.7109

o High E-fields of colliding bunches, intense BS causing distortion in

luminosity spectrum, incoherent production of

e+e- pairs, hadron production from

o Deposition of 19 TeV visible energy per train

in calorimeters o Drives timing

requirements:10 ns time-stamping +PFA to remove

background

Trade-off between occupancies and reconstruction (i.e VTX pixel size, calorimeter integration time vs. bck.)

REQUIREMENTS FROM THE BEAM CONDITIONS

High tracker occupancies small cell sizes BCK energy high-granularity calorimetry

FCAL radiation hardness

(3105 inc. pairs/BX at 3TeV) BCK suppression overall need for precise hit timing

~10 ns hit time-stamping in tracking

1 ns accuracy for calorimeter hits Low duty-cycle triggerless readout (read all after 156 ns

train) Incoherent pair background determines: angular coverage of

vertex detector, forward tracking discs; FCAL apertures/technologies, design of beam pipe


Vertex detector – ultra lightCalorimetry – ultra heavy and compact

DETECTOR CONCEPTS


o Based on initial ILC concepts (ILD and SiD)o Optimized and adapted to CLIC conditions

The aim is to have one optimized concept – end 2014


Optimization studies linked to physics performance(flavor-tagging, Ejet resolution, forward region coverage)

DETECTOR OPTIMIZATION STUDIES In order to achieve detector:

o Adapted to physics needs (Higgs measurement prospects, EW precision measurement, discovery reach for BSM physics)o With manageable occupancieso Realistic and cost-effective technology solutions

Parallel work on detector optimization in several areas:

o Vertex detector optimizationo Forward region studieso ECAL optimization studieso and other (e.g. aspect ratio, tracker radius, barrel/endcap transition, B-field)

VERTEX DETECTOR OPTIMIZATION: FLAVOUR TAGGING


5 barrel and 4 FVD single layers

3 barrel and 3 FVD

double layers

a. Similar performance for both layouts

b. The material budget has a larger impact than the geometry.

b-tagging performancea. b.

More in talk by Philipp Roloff

ECAL OPTIMIZATION STUDIES


o PFlow calorimetry requiresreconstruction of four-vectors of all

visible particles in an event. o The momenta of charged

particles are measured in the tracking detectors, while the energy

measurements for photons and neutral hadrons are obtained from the

calorimeters .o In PFA it’s needed to perfectly

associate all energy deposits with the correct particles (confusion term) drives granularity requirements

o Granularity requirements and use of Si as active material make the ECAL

expensive.

Studies of scintillator based calorimeters instead of silicon as active layer – cost driven by Si surface (~2600 m2 ILD_ECAL)

ECAL OPTIMIZATION: EJET RESOLUTION


o For models using Si or scintillator (Sc) as the active material, recent simulation studies have examined

variation of jet energy resolution as a function of

key ECAL parameters:Transverse granularity; Number of

layers; Inner radius; B-Field strength and Sc thickness.

o Have also examined novel ECAL models that use Si for the first few

active layers, then move to Sc deeper in the calorimeter. Width of

Sc cell sizes can increase with calorimeter depth. Comparable performance of

Si and Sc as active materials

HARDWARE R&D - VERTEX DETECTOR


o Various R&D aspects for CLIC Vertex Detector are covering broad spectrum of technologies (sensors, support, cabling, powering, cooling, readout, DAQ, assembly) o Integrated R&D effort simultaneously addressing CLIC vertex detectorchallenges

More in talks by D. Dannheim, F.X. Nuiry, P. Roloff

VERTEX DETECTOR R&D – THIN SENSORSHybrid technology option: Low-power and small-pitch readout ASICs (Timepix) bonded to ultra-thin sensors


VERTEX DETECTOR R&D – HV-CMOS ACTIVE SENSOR WITH CAPACITIVE COUPLING


o 65 nm CMOS technology, 6464 pixel matrix (25 m pitch) o Combined prototype for ATLAS and CLIC

VERTEX DETECTOR R&D – AIR COOLING AND LOW-MASS SUPPORT


o The power dissipation of the readout chips is reduced by means of power pulsing, allowing for a cooling system based on a forced gas (dry air) flow.o Preliminary validation results suggest that air flow cooling with low-mass supports is feasible

CALORIMETRY R&D -SHOWER TIMING IN TUNGSTEN HCAL


o Key reconstruction challenge at CLIC: Pile-up of hadronic background from several bunch crossings (i.e 19 TeV depositions in calorimeters over 20 BX)o Rejection via timing cuts – relies on timing in calorimeterso Precise modeling of time structure of hadronic showers is crucial

arXiv:1404.6454

Demonstrated importance for tungsten absorbers of using high precision treatment of low-energy neutrons in physics models

CALICE T3B (setup of 15 small plastic scintillator tiles read out with Silicon Photomultipliers): A dedicated experiment to measure the time structure of showers in tungsten absorbers

CALORIMETRY R&D-SCINTILATOR -TUNGSTEN HCAL IN THE TEST-BEAM


o Analysis of test beam data of highly granular scintillator-tungsten HCAL (high-momentum 10-100 GeV e+, +, K+, p) o Measurement of response, energy resolution and shower shapes

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o Demonstrated linearity of detector responseo Energy resolution well described by:

o Reasonably good agreement between data and Geant4 models, room for improvement

FCAL R&D


o Electrical characterization done for 40 prototypes LumiCal sensors (strip pitch 2.2 mm) and 30 prototypes of compensated GaAs sensors (BeamCal); o Sensor + Front-end ASIC+ ADC ASIC ( 32 channels fully equipped) in the test-beam (2-4.5 GeV electrons at DESY)o Future: novel connectivity technology (e.g. bump bonding, thin fan-out PCB), construction of a demonstrator calorimeter, test E and resolution and biaseso

Impact point reconstruction using the beam telescope - LumiCal sensor

average S/N ratio ~19

Probe station for BeamCal sensor characterization

o S/N ~19 for all channels.o Independent pad areas show identical charge collection.o Homogeneous response of the pad signal.o Edges-loss of about 10% of the signal.

SOFTWARE DEVELOPMENT – DETECTOR DESCRIPTION FOR HEP


oDD4Hep Single source of information for simulation, reconstruction, visualizationo DD4Hep validation: Comparing performance for one full concept(CLIC_ILD or CLIC_SiD)o New CLIC detector model - Only one concept implemented in DD4Hep

SOFTWARE DEVELOPMENT – ILC DIRAC GRID INTERFACE


o More and more users in the LC community (CLIC, ILD, SiD, Calice)o Move to CVMFS for software distributiono Include interface for new applications: Whizard2, DD4hep based sim. programso Upgrade to new DIRAC version, move to virtual machine infrastructure for better performance and reliability

ILCDirac GRID interface for centralized productionhttp://ilcdirac.cern.ch

CPU Time in years, used on different grid sites in the last 6 months(production and users)

User jobs per hour during the last 6 months

Many thanks to the GRID site administrators for their supportSpecial thanks to Strasbourg administrators who unfortunately had to stop their support for the ILC virtual organization

CLICdp AWLC talks

STATUS OF THE ONGOING HIGGS ANALYSES

o 350 GeV: SM precision measurements, Higgs-recoil, top masso 1.4 TeV: rare Higgs decays, Higgs self-coupling, BSM discovery o 3 TeV: highest precision for rare decays and self-coupling, highest discovery reach


SINGLE HIGGS PRODUCTION AT CLIC


Large samples of Higgs bosons can be produced at CLIC

Already at 350 GeV by far surpassing the number of W bosons at LEP

Higgs production at various stages with unploarized beams. Polarization (-80,+30)% can enhance x-sections for HZ and H for a factor of 1.4/2.3

σ ~ log(s)

σ ~ 1/s

VV fusion V=Z,W

Higgsstrahlung


o Absolute measurement of the gHZZ can be obtained from recoil mass distribution in Ze+e-,+- decays. However, BR(Z ll) l=e, is small ~3.4%

o Exploit BR(Z qq) ~ 69%o Improvement in precision by a factor 2 compared to leptonic decayso Challenge: Z → qq reconstruction may depend on Higgs decay mode – separation of H and Z hadronic decays in multy-jet topologyo Ongoing study: bias seems very small

See talk by M. Thomson

σ(HZ) at 350 GeV using Z→qqq q

Δ(σHZ) / σHZ ≈ 2% → Δ(gHZZ) / gHZZ ≈ 1% from hadronic Z decays


o The strongest Higgs fermion couplingo ttH directly sensitive to gttH

o Test coupling-mass linearityo Can be influenced by BSM physics o Complicated multy-jet topologies (6/8 jets)o Jet clustering, b-tagging o MVA needed (20 variables)o Combination of both final states gives at 1.4 TeV

PROCESSES AT HIGHER ENERGIES

More in talk by P. Roloff

Double Higgs

production

ttH production – top Yukawa coupling

o Sensitive to the Higgs self-coupling

λ at O(10%/16%) with polarized/

unpolarized beams

o Sensitive to the quartic HHWW

coupling O(3%)

o Requires higher CM energies and

polarization

OTHER HIGGS PHYSICS ANALYSES PRESENTED AT AWLC


o F. Simon H → bb/cc/gg at 350 and 1.4 TeV -Large x-sections lead to small statistical errors, allows precision mH measurement, test SM predictions (linearity, gHcc/gHbb ratio)o C. Grefe H → γγ and H → Zγ at 1.4 TeV- Induced by loops over heavy charged particles sensitive to BSM physics, rare decays BR~10-3, can be improved by polarizationo S. Lukic H →WW* at 350 GeV and 1.4 TeV- Knowing gHWW , HWW* decay provides the H at the percent levelo A. Robson Higgs production in ZZ fusion- Direct access to gHZZ (H) with inclusive H decays, Hbb final state promising for gHZZ/gHWW ratio determination without explicit knowledge of gHbb or H

12 CLICdp AWLC talks: 7 physics + 5 detector related

OVERVIEW OF ALLCLIC HIGGS STUDIES


o ZH, absolute determination of the production x-section O(2%), sensibility to invisible decay modes to BRinv~1%o ZH, Zee,, qq absolute determination gHZZ O(1%) (comparable sensitivity at 350 GeV and 250 GeV)

o WW fusion, relative couplings to gHWW / gHZZ can be determined at O(1%) – SM testo WW fusion, other relative BR measurements i.e. gHcc / gHbb O(1.5%), Higgs rare decaysStatistics can be improved

by polarization up to a factor 2.3

* preliminary estimates

Physics at the CLIC e+e- Linear Collider -- Input to the Snowmass process 2013, July 2013, arXiv:1307.5288

NEEDS UPDATE

MODEL INDEPENDENT HIGGS COUPLINGS AND WIDTH MEASUREMENTS

oFit to results shown on the previous slideo Fully model-independent, only possible at a lepton collidero All results limited by 1% from σ(HZ) measuremento The Higgs width is extracted with 5.5% - 4% precisiono High range of Higgs boson couplings can be measured at the O(2%) levelo Higgs trilinear self-coupling parameter can be measured at the 10% (highest CM energy, beam polarization)


NEEDS UPDATE

See talk by F. Simon

ANALYSIS SIMILAR TO LHC EXPERIMENTS


o Alternatively, fit can be performed using 9 scale factors i

o

o H,model is a sum of SM partial widths – no invisible decayso

o Sub-percent precisions achievable at high energyo Results are strongly dependent on fit assumptions

NEEDS UPDATE

ABOUT CLICdp

Collaboration of 23 institutes from 17 countries

+ UK , University of Bristol

You can find CLICdp at:

CLICdp home-pagehttp://clicdp.web.cern.ch/


http://clicdp.web.cern.ch/

CONCLUSIONS

- Physics driven detector design and optimization is leading towards one detector concept – end of 2014.

- Current focus is on hardware required for detector at CLIC, including optimization, engineering and integration studies.


Wide range of physics analyses, including full detector simulation and background from physics and machine related processes, have demonstrated:

- Understanding of detector performance requirements;

- Precision Higgs physics capabilities in CLIC environment, complementary to HL-LHC, in some aspects going significantly beyond.

BACKUP

CLIC CALORIMETRY - DESIGN

B1 I. Bozovic Jelisavcic CLIC Detector & Physics Status AWLC 2014, Fermilab, 12-16 May 2014

ECALSi or Scint. + Tungsten cell sizes 13 mm2 or 25 mm2 30 layers in depth

HCALSeveral technology options: scint. + RPCTungsten (barrel), steel (endcap)cell sizes 9 cm2 (analog) or 1 cm2

(digital) 60-75 layers in depth (HCAL depth ~7 Λi)

REQUIREMENTS

VERTEX DETECTOR – R&D

Production and assembly of thin sensors: 100, 150, 200 and 300 μm sensors delivered (50 μm under consideration)

Spiral disks allow air flow through detector: air cooling seems feasible (ANSYS finite element simulation)

Demonstrator chip with fully functional 6464 pixel matrix in 65 nm CMOS technology; 100 chips delivered in February 2013 see more in D. Dannheim and François-Xavier NUIRY’s talks


Various R&D aspects for CLIC Vertex Detector are covering broad spectrum of technologies (sensors, support, cabling, powering, cooling, readout, DAQ, assembly)

Low leakage currents ~ 1 nA


H DECAY

o Large x-sections lead to small statistical errors

o Allows Higgs mass determinationmH ~ 30 MeV at energies above 1 TeV

o Jet-energy resolution and flavor-tagging of crucial importance

o Does flavor-tagging survive background? Yes

o Serve to test coupling-mass linearityo Test SM prediction for gHbb/gHcc

%7.2)ccH(BR

%2.0)bbH(BR

prod

prod

bb, cc, gg


o Induced by loops over heavy charged particles sensitive to BSM physics

o Rare decays, BRs ~ 0.16% and 0.23%

o Large background - MVA

o stat(HBR(H)) ~ 14.7%

o stat(HBR(HZ)) ~ 41% due to limited signal efficiency of <25%

o The later can be improved by beam polarization up to 27% for (-80,+30)%

HZ, H DECAYS AT 1.4 TEV

See talk by C. Grefe


HIGGS ANALYSES : WW FUSION, HWW* DECAY

o ZH can be used to determine gHZZ O(1%)o Once gHZZ is known, gHWW can be determined from WW fusion Hbb in a model-independent way:

o Knowing gHWW , HWW* decay provides the total Higgs decay width:

o Can be determined with 1.1% statistical accuracy (1.4 TeV) and 2% (350 GeV)o This way, H~8% uncertainty is achievable (all energy stages, -80% polarization) going down to 4% in combined fits

See S. Lukic talk


o Hee~10% H; Hee 24.5 fbo Direct access to gHZZ (H) with inclusive H decays/limited sensitivityo Explicitly requiring Hbb using b-tag gives clean signal separation

o stat(HeeBR(Hbb)) ~ 1.5%

o Promising for the gHZZ/gHWW ratio without knowing gHbb or H

o Main systematics comes from the detector (electron) acceptance in

Hee

See A. Robson talk

x 8

HIGGS ANALYSES : H PRODUCTION IN ZZ FUZION

OTHER CLIC PHYSICSBENCHMARKS


o Scales well beyond available CM energy accessible

o SUSY masses and anomalous couplings measurable at the percent level or better

o top Yukawa coupling can be measured at O(4%) at CM>1 TeV

o Generally more precise than LHC/HL-LHC

o Some searches (Higgs, Emiss signatures) can be done in a model-independent way

clic detector and physics status

Documents

physics status clic

tev clic

clic conditions

bsm physics

ongoing higgs physics

ns accuracy

ns timestamping pfa

high efields