Physics Requirements for the ILC Vertex Tracker

Physics Requirements for the ILC Vertex Tracker

Marco BattagliaUC Berkeley and LBNL

WWS ILC Vertex Tracker ReviewOctober 22, 2007

Physics Scenarios for the ILC Vertex TrackerPhysics Scenarios for the ILC Vertex Tracker

Test the SM through precision study of the Higgs boson profile;

Investigate nature of new physics beyond the SM and its relation with Cosmology;

Search for new phenomena through precision EW data;

Ecm

(TeV)bbbb qqqq

0.5 15 fb 23 fb 500 fb

1.0 3.0 fb 45 fb 140 fb

Benchmarking the ILC Vertex TrackerBenchmarking the ILC Vertex Tracker

Develop list of benchmark processes where i) ILC physics scenarios broadly covered, ii) benchmarks robust and retain wider scope, iii) detector performance manifest in direct way, iv) target performance motivated by quantitatively well-defined requirements.

Benchmarks for the ILC Vertex TrackerBenchmarks for the ILC Vertex Tracker

ILC Physics SignaturesILC Physics Signatures

ILC Physics program has possibly the broadest range of particle kinematics and event topologies;

Within a single physics scenario, DM-motivated Supersymmetry, below are some of the signal signatures which need to be measuredwith O(0.1 - 1%) accuracy:

Physics Objects from the ILC Vertex TrackerPhysics Objects from the ILC Vertex Tracker

Particle Track Compatibility with a Vertex

Vertex Charge

Charged Particle Mass

Particle Track Seeds

Charged Particle Momentum

Requirements for ILC Vertex TrackerRequirements for ILC Vertex Tracker

tp

ba

Asymptotic I.P. Resolution [ a ]

Multiple Scattering

I.P. Term [ b ]

Polar Angle Coverage

Space / TimeGranularity

The Physics MatrixThe Physics Matrix

Testing the SM Understanding

New Physics

Probing the

TeraScale

Asymptotic I.P.

resolution (a)HSMbb,

e+eHHZ, HH

HAbbbbH

Multiple Scattering I.P. Term (b)

HSMcc,gg

e+eHHZ

CP violation H

(e+ebb,cc)

Polar Angle Coverage

AFB e+eHHZ, HH

Space/Time

GranularityBkg Bkg (e+ebb,cc)

Bkg

Requirements for ILC VertexingRequirements for ILC Vertexing

a (m) b (m GeV)

LEP 25 70

SLD 8 33

LHC 12 70

RHIC II 14 12

ILC 5 10

tip pba /tip pba /

ILC Vertexing

Asymptotic I.P. ResolutionAsymptotic I.P. Resolution

Vertex Tracker, eVertex Tracker, e++eeHH00AA00 and Dark Matter and Dark Matter

Understanding the nature of Dark Matter in the Universe and match the accuracy on its relic density from satellite expts with collider data requires highly accurate determinations of masses andcouplings of new particles responsible for DM and its annihilation in early Universe:

Example of SUSY DM

ee++eeHH00AA00bbbb,bbbb,bbbb at 1.0 TeV at 1.0 TeV

ILC unique to achieve the ~0.25% accuracy on the A0 mass needed to predict matching CMB WMAP precision;

Need to tag bbbb final state high efficiency (HA ~ 1fb and 4b jets to tag) and small misid (bkg/signal ~ 4 x 103 ), tagging important to fix additional SUSY parameters:

Battaglia, Hooberman LCWS07, ALCPG07

Full G4+MarlinReco

ee++eeHH00ZZ00, H, H00; H; H00++--, ,

Fundamental test of Higgs mechanism requires verifying that its couplingsto fermions scale as fermion masses, not only ILC can do this to limiting mfaccuracy for quarks but can also perform first test in leptonic sector;

Vertex Tracker plays major role to tag leptons, improve p/p for s;essential excellent single point resolution for stiff, closely collimated () or isolated (,) particle tracks;

Ecm

TeV

MH

120 140

gH/gH0.5 0.027 0.050

gH/gH0.8 0.150

b-Jet Energy at 0.35 – 1.0 TeVb-Jet Energy at 0.35 – 1.0 TeV

Semileptonic b decays [BR(bcl) = 0.22] introduce loss of jet energy due to escaping , which causes smearing to mass and energy reconstruction;

Can identify through tag of leptonwith significant ip and correct usingcombination of jet p vector and pri.-sec. vtx vector.

Identify Light HIdentify Light H in large tan in large tan SUSY SUSY

SUSY scenarios with light charged Higgs bosons and large tan bring H signature which can be distinguished from W using polarization (RH vs. LH s);

If mH- < mtop, study can be performed in recoil of hadronic top and experimental challeng is to tell decay over broad momentum range;

Vertex Tracker must identify single-prong at moderate to large momenta;

Boos, Carena, Wagner, hep-ph/0507100

Multiple Scattering I.P. TermMultiple Scattering I.P. Term

Multiple ScatteringMultiple Scattering

e+e- HZbb+- at ILC 0.5 TeV

Despite large centre-of-massenergies, most charged particles are produced with rather moderate energies: interesting processes have large jet multiplicity (4 and 6 parton processes + hard gluonradiation) or large missing energiesWW and ZZ fusion processes and SUSY with conserved R-parity;

Excellent track extrapolation at low momenta essential for secondaryparticle track counting, scenarios with very soft single prongs.

HH00bb, cc, gg at 0.35 - 0.5 TeVbb, cc, gg at 0.35 - 0.5 TeV

Determination of Higgs hadronic branching fractions, one of the most crucialtests of the Higgs mechanism of mass generation and unique to the ILC forthe experimental accuracy needed to match theory uncertainties and probeextended Higgs sector models;


Determination of Higgs hadronic branching fractions, one of the most crucialtests of the Higgs mechanism of mass generation and unique to the ILC;

Light Higgs boson offers opportunity and challenge: couplings to b, c and tquark accessible, but need to tag b, c, light jets with 70 : 3 : 7 ratio in signal.

120GeV BR(HX)/BR

Hbb

Hcc

Hgg

%0.1%3.12%3.8

Kuhl, DeschLC-PHSM-2007-001


Yu et al.J. Korean Phys. Soc. 50 (2007);

Kuhl, DeschLC-PHSM-2007-001;Ciborowski,Luzniak

Snowmass 2005

Channel Change Rel. Change in

Stat. Uncertainty

Hbb

Hcc

Hgg

Geometry:5 4 layer VTXThickness: 50 m 100 m

+ 0%

+15%

+ 5%

Hccpoint:

4 m 6 m4 m 2 m

+10%-10%

Hcc

Thickness:

50 m 100 m +10%

Degradation in performance correspond to 20-30% equivalent Luminosity loss.

Higgs PotentialHiggs Potential

ILC offers unique opportunity to study the shape of the Higgs potential throughmeasurement of Higgs self-coupling in HHZ and HH at 0.5 and 1TeV

Battaglia, Boos, Yao, Snowmass 2001

ee++eeHH00HH00ZZ0 0 at 0.5 TeVat 0.5 TeV

Boumediene, Gay, LCWS07

ILC offers unique opportunity to study the shape of the Higgs potential throughmeasurement of Higgs self-coupling in HHZ and HH at 0.5 and 1TeVIsolating HHZ signal (=0.18pb) from tt (s=530pb), ZZZ (=1.1pb), tbtb (s=0.7pb) and ttZ (s=0.7pb) is an experimental tour-de-force;b-tagging and jet energy resolution essential to suppress backgrounds;

L = 2 ab-1

Full G4+MarlinReco

ee++eeHH00HH00ZZ0 0 at 0.5 TeVat 0.5 TeV

Boumediene, Gay, LCWS07

HHZ

tt

ZZZttZ

tbtb

c(%) 25 35

b = 90%HHqq channel

c(%) 5 35

ttWbWbbbcscs with mis-taggedcharm jets resembles bbbbqq signal;

CP-violation in HCP-violation in H Decays Decays

SUSY loop contributions may induce sizeable CP asymmetries in heavy Higgs boson decays:

Asymmetry can be measured with quark-antiquark tagging, need to usehadronic top decays and adopt vertex charge algorithm for b and c jets.

Vertex Tracker, eVertex Tracker, e++ee1111, DM, DM

Essential to reject bkg ee eeby low angle electron tagging and ee, ee also by i.p. tag:

Bambade et al.LCWS04

In co-Annihilation SUSY scenarios DM density controlled by stau-LSP mass splittingsensitivity to small M depends on background rejection:

ee++eeqq at High Energy Frontierqq at High Energy Frontier

Indirect effect of exchange of new particles in Standard Modelprocesses offers unique window to search for new phenomenaat scales >> centre-of-mass energies:

Cross sections Asymmetries

Fermion Tag,Efficiency, Purity

Fermion Tag,Charge ID,Beam Polarization

ee++eecc at 0.5 – 1.0 TeVcc at 0.5 – 1.0 TeV

ee++eecc at 0.5 TeVcc at 0.5 TeV

c = 0.5

c = 0.29ff (pb)

cc 0.74

bb 0.40

0.45

Measurement of cc cross section:moderate cross section, requires 2 tags and low background;

AAFBFB in e in e++eecc at 0.5 – 1.0 TeVcc at 0.5 – 1.0 TeV

ee++eecc at 0.5 TeVcc at 0.5 TeVFurther sensitivity on NP scaleand nature can be obtained with Acc

FB determination;

Experience at LEP with Jet charge algorithms;

Improved sensitivity expectedusing vertex charge, requiresfwd coverage;

Geometry IP (m)

R1 1.2 cm 1.7 cm

c purity=0.7 c = 0.49

c = 0.46R1 1.2 cm 2.1 cm

c purity=0.7 c = 0.49

c = 0.40

HPS c purity=0.7 c = 0.29

tp/74

tp/104

tp/145.5

tp/74

Hawking, LC-PHSM-2000-021

Total efficiency = N with N = number of jets to be tagged

tp/1511

Charm Tagging vs. I.P. Resolution

Study change in efficiency of charm tagging in Z0-like flavour composition

Vertex ChargeVertex Charge

Vertex charge algorithmsvery promising for q-anti qdiscrimination in b and c jets

Vertex charge extremely sensitive to correct secondaryparticle tags: any mistake changes result by 1

Hillert & LCFIRingberg 2006

Benchmark vertex charge performance using P(B0B ) :

(SGV Fast Simulation)

hadrons at 0.35 – 1.0 TeVhadrons at 0.35 – 1.0 TeV

Battaglia, Schulte, LC-PHSM-2000-052

Underlying bkg from hadrons create source ofconfusion in event reco and selection;

e+eWWH0 crucial process to determinegHWW and H whose selection relies on missingenergy and recoil mass: both are distorted by additional hadronic activity;

e+eWWH0hadronsat 0.35 TeV ILC

Expect 0.10-0.15 hadrons events /BX mostlyfwd peaked;

Tracks from hadrons events, occuring randomly within bunch envelope, characterised by i.p. w.r.t. physics event large along z and small in R

Likelihood based on precise i.p. measurements in both projection provides rejection of spurious particle tracks with only 20% efficiency loss.

G3 Simulation

Hadronic InteractionsHadronic Interactions

Jeffery, HillertLCWS07

Ladder thickness is not only causing distortions in track extrapolationbut also hadronic interaction which adversely affect rejection of lightquarks;

Polar Angle CoveragePolar Angle Coverage

Weak Boson Fusion, t-channel and processes with large multiplicity final states require coverage for tracking/tagging close to beam axis;

The Importance of Being Forward

e+e110 at 0.5 TeV

polar angle

e+eH0H0bbbb at 1 TeV

H0 polar angle

Beyond observation of deviation from SM, analysis of polar angle dependence of EW observables provides discriminationbetween New Physics models:

Extra Dimensions, Extra Gauge Bosons,Radions, ...

AFB

Hewett, Riemann

Polar Angle Analysis of EW Observables

Long vs. Short Barrel Section


Space & Time GranularitySpace & Time Granularity

Incoherent Pair BackgroundIncoherent Pair Background

Maruyama, LCWS07

SiD0.5 TeV20 stat independent BXs

LDC

Vogel, LCWS07

Occupancy LimitationsOccupancy Limitations

4th Concept Fake Track Reconstruction Study

Ecm = 250 GeVIntegrate 140 BXGuineaPig Pair SimulationBackground OnlyG4 Simulation + ILCRoot:

163 VTX Only Tracks176 VTX+TPC Tracks C. Gatto, LCWS07,

Sim/Reco Parallel Session


Nagamine, LCWS07

Track Finding Efficiency in Vertex Tracker using layer doublets


Standalone PatRec in VTX in presence of Pair Background

(Full G3 Simulation)



Standalone PatRec in VTX in presence of Pair Background

Raspereza,LCWS07

(Full G4 Simulation + MarlinReco)


20m pixels response to ALS beam after Al scraper

Understand cluster shape/occupancy of low momentum pairs striking detectorsat small angle and use shape to possibly discriminate them;

Very fascinating and compelling anticipated physics programwith crucial contributions from Vertex Tracker;

Significant simulation and reconstruction efforts by many of the groups involved in sensor R&D and detector design;

Essential to promote vigorous program of physics benchmark studies using full simulation and reconstruction and realisticbackground conditions to guide R&D and design.

Documents

Physics Requirements for the ILC Vertex Tracker