1 a.de roeck cern 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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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
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