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A.De RoeckCERN

Amsterdam, April 2003

e-e-, gamma-gamma and e-gamma options for a Linear Collider

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In this study

• Gamma-gamma and e-gamma option– Working group on gamma-gamma/e-gamma collider technology K. Moenig and V. Telnov– Working group on gamma-gamma physics M. Kraemer, M. Krawczyk, S. Maxfield, ADR, (S. Soldner- Rembold)

• 4+2 meetings during this study • During ECFA/DESY, integrated with other physics groups/

worked well!• Many new results

• e-e- option– No new studies in the context of this workshop/ 2 meetings St

Malo/Amsterdam C. Heusch• Will remind some key issues based on Snowmass/Jeju

reports

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e-e-optionAdvantages of e-e-: Large polarization for both beams: eL,eR

Exotic quantum numbers (H--) Larger sensitivity in some processes Some very clean processes

No s-channel, lower luminosity

Non-Commutative QED

Sensitivity to contact interactions

…Majorana neutrinos

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e-e- optionHiggs production

Supersymmetry

CP viol.phases

But: No detector simulation, IR, beamstrahlung, selectron width…

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e-e- optionParameters (Snowmass 2001)Study for TESLA (S. Schreiber)

Luminosity 5-(10)•1033 cm-2 s-1

L e-e- = 1/6 –(1/3) L e+e-

Stability ~OK with intra-train feedback system

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e-e- option

Future control room at the FLC??

No major changesrequired in IPor accelerator

e-e- is the optionwhich will be mosteasily to realize(for TESLA)

Has to be kepton the roadmap

S. Schreiber

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Gamma-gamma and e-gamma

Compton backscattering on laser photons Needs second interaction point Needs crossing angle Peaked but smeared spectrum

Hence: needs extra effort Is it worthwile? Jeju panel discusion: Yes!

Examples of advantages Higher cross sections for charg. particles Different JPC state than in e+e- Higgs s-channel produced Higher mass reach in some scenarios CP analysis opportunities Can test precisely couplings to photons…

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Gamma-gamma and e-gamma

• TESLA-TDR/ PLC workshop Hamburg 2000 Golden processes identified Starting point in Krakow Only light Higgsbb and QCD processes simulated

(simplified)• This study: Level of detail in as good as in e+e-

– SIMDET simulation for more golden processes• H WW, ZZ , Heavy MSSM H & A, WW production, Susy

– Cross checks/elaborate for key process Higgs bb – Further opportunities: CP studies, Extra Dimensions, NC

QED,..– Real luminosity spectra/polarization used (CIRCE, CompAZ)– B search using ZVTOP– Adding overlap events – QCD backgrounds in NLO– QCD Monte Carlo tuning to existing data

• Direct contact & exchange with the US studies/exchange tools

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Gamma-gamma and e-gamma

• Backgrounds and Luminosity – Luminosity/polarisation measurement (&

corresponding syst.)– Background studies (pairs, photons, neutrons)– Evaluate design of IP/Mask/vertex detectors

• Technology– R&D efforts in Europe and the US

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Golden Processeshep-ph/0103090

Higgs

SUSY

Tril/quart.

Top

QCD

TDR

Being done or ready: should be ready for the writeup promised

NOW

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Golden ProcessesAdded at/since the Krakow meeting: Non-commutative QED e for ED’s Light gravitinos Radions Gluino production H (US groups) HH+H- (US groups) CP analyses in the Higgs sector

More (as yet uncovered/lower priority at present) ee* Leptoquarks Strong WW scattering eeH As always: still room for volunteers (next workshop)

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Gamma-gamma and e-gamma

Information on lumi spectra, special SIMDET version, background…

On our group web page…

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Luminosity Spectra

Luminosities files with PHOCOL (V. Telnov)Can be used via CIRCE (T. Ohl)Analytical approximation COMPAZ (A. Zarnecki)

TDR parameters

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Luminosity Measurement• Proposals

– ee ee () / not for J=0– ee ee () – ee 4 leptons

• Precision ~0.1% (stat)• For Higgs (J=0) e.g. ee ee

For e collisions- e e - e eee

Moenig,Marfin,Telnov

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Monte Carlos & Tuning

• Amegic & Wing

SHERPA Generator (F. Kraus et al.)

Tuning of the Monte Carlo modelsvia JETWEB (M. Wing)

A tune for LC studies has been produced

Resolved

Direct

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Background studies backgrounds studied for TESLA IP layout

Study beam related background

# of QCD events overlapping now under control ( 1 evt@ 200 GeV and 2.5 evts @500 GeV). All groups agree (D. Asner, ADR, Telnov, Warsaw)

# of hits in the layers of the pixel detector per bunch crossing Incoherent pair production: essentially the same as for e+e- Coherent pair production: High! but ok, similar to e+e- same vertex detector as for e+e- (Moenig,Sekaric) Neutrons? Probably ok (V. Telnov)

Moenig et al

1st layer

2nd layer…

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QCD

To be used in the Monte Carlo programs

QCD had been mostly studied --at detector level-- for the TDR Not revisited this time

Exceptions (using new data)Total cross section parametrizations (Kwiecinski, Motyka,Timneanu) & (Pancheri, Grau, Godbole, ADR) Structure functions PDFs (Krawczyk et al.)

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Higgs

Heralded as THE key measurement forthe gamma-gamma option

• From the TDR (Jikia, Soldner-Rembold) • This workshop

– Study H bb, with realistic spectra, background, B-tagging efficiency,…

– Study H WW,ZZ– Study model separation power– Study spin of Higgs in H WW,ZZ– Study CP properties of the Higgs – Study MSSM Higgs (H,A): extend e+e- reach– Study of the Charged Higgs (US) 250 350

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3

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Using NLO backgrounds (Jikia…) Next question: Systematics…??

SM Higgs analyses

1 year/84 fb-1

P. Niezurawski

Corrected inv. mass

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SM Higgs Analysis

• Analysis of a second group (Zeuthen)– Taking into account the QCD

radiative corrections to the background process (Pythia + NLO Xsec.) through a reweighting procedure.

– Adopting a b-quark tagging algorithm based on a neural network.

events 7111N

events 6018 N

bkg

sig

A. Rosca

. fb 80 1-L

= 1.9%

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SM Higgs: HWW,ZZ

Simultaneous determination of the Higgs Boson width and phase H WW and H ZZ measurements(full detector simulation)

/ = 3-10% MH< 350 GeV

A. Zarnecki

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SM Higgs Analysis

120 130 140 150 160

1.8 1.9 2.2 3.0 6.8

MHbb (GeV) /

Warsaw group

Different masses

2HDM SM-like versus SM(Ginzburg et al.)

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MSSM H/A Higgs

Extend the detailed analysis to H/A bb

P. Niezurawski

One year running and s 500 GeV

A0 detectable for MA > 300 GeV beyond the e+e- reach

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MSSM H/A Higgs

D.Asner/J.Gunion (LCWS02)

Extends e+e- reach Need few years to close the LHC wedge

European study in progress

Study for a e+e- colliderat 630 GeV

e+e-

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Angular distributions in hZZlljj and hWW4j

D. Miller et al. hep-ph/0210077

Higgs spin and parity

Detector effectsare large, but sensitivity left

A. Zarnecki

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CP studies via ttR. Godbole et al.hep-ph/021136 & LCWS02

Exciting possibility to analyse CP structure ofthe scalar

Construct combinedasymmetries fromintial lepton polarizationand decay lepton charge

Done with Compton spectraUsing COMPAZ reducessensitivity with factor 2

Needs detector simulation

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real /parasitic

Ee= 450 GeV

∫Lt=110 fb-1

E= 400 GeV

∫Lt=110 fb-1

Eee= 500 GeV

∫Lt=500 fb-1

L 0.1% 0.1%

·10-4 10 / 10 / (9.9)

6.73.1

·10-4 15 / 22/ (2.6)

6.04.3

sensitivity ~ proportional to the momentum of the particles involved in the triple gauge boson vertex

Sekaric, MoenigBosovic, AnipkoIncludes detector simulation/3D fits

Studies starting for quartic couplings in WW and WWZ I MarfinUse of optimal variables F. Nagel et al.

Study WW eW

Triple Gauge Couplings

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Extra Dimensions

tt

ADD type extra dimensionsSensitivity to mass Ms

Ideal Compton spectrum COMPAZ spectrum

P. Poulose

Realism reduces sensitivity: Ms=1.7 TeV to 1.4 TeV

SM+2

SM-2

see=500 GeV

=+1

=-1

MsMs

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Supersymmetry

Several analyses starting charginos squarks eslepton neutralinoWill be pursued up to the detector level E.g.

Kraus, Wengler

Theoretical studies: gluinos

Interesting but needs simulation

Klasen, Berge

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Technology• Photon collider IP introduces new challenges

– Laser– Optics– Stability & control in the IP (1nm?) /length control in cavity – Extraction line…

• Both Europe & US groups have and R&D effort.– Europe: use a cavity to reduce laser power– US: full power laser design

• US: laser commissioning 20 J pulses at 10 Hz / Full power next year– interferometery for alignment– ½ size focusing optics setup in lab– beam-beam deflection feedback system study– PC testbed at SLAC? Proposal under preparation

• Europe : study cavitiy option– Make 1:9 size test cavity? Wait for funding/technology decision?

Funding is an issue to continue R&D!

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Interferometric Alignment System Testbed at LLNL

• Half-scale prototype of optics / alignment system to test mirror quality and alignment scheme– Optics and laser interferometer currently installed

J. Gronberg

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Engineering Test Facility at SLCRevive SLC and install beampipe with

opticsto produce luminosity

Beam EnergyDRx,y (m-rad)

FFx,y (m-rad)

x / y

z

x,y

N

30 GeV

1100 / 50

8 / 0.1 mm

0.1 – 1.0 mm

1500/55nm

6.0E9

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G. Klemz

New proposal

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Conclusions

• Lot of activity on gamma-gamma during this workshop series– Good balance found between gamma-gamma specific meetings

and integration with the other groups• Good progress on tools/background etc, for gamma-gamma studies • Many detailed studies

– The light Higgs results confirmed and extended / ~ 2%

– Higgs channels in WW,ZZ studied / ~ 3-10%

– H/A study confirms reach for high masses, beyond e+e-– CP, Higgs spin etc studies starting– Detailed study of the TGCs measurement competitive with

e+e-– First results on SUSY and Extra Dimensions/alternatives explore during the continuation of the workshop

Confirms /e as an exciting option for a LC !• Progress also with hardware plans (PC testbed/Berlin studies)Big thanks to all participants, particularly the Warsaw and Zeuthen Groups