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Gamma-gamma Physics Group Report

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Common session with QCD (1 talk) Common session with Higgs ... AMEGIC for. S. Schumann, F. Kraus. Resolved. Direct. Event generator AMEGIC 5. AMEGIC for ... – PowerPoint PPT presentation

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Title: Gamma-gamma Physics Group Report


1
Gamma-gamma Physics Group Report
  • De Roeck
  • CERN

2
This meeting
  • Sessions
  • Gamma gamma session (3 talks)
  • (including a Report from LCWS02 by M
    Krawczyk)
  • Common session with QCD (1 talk)
  • Common session with Higgs (6 talks)
  • Common session with EW ( 2 talks)
  • Jeju Photon Collider option discussion (Higgs
    group)
  • Physics case for PC has confirmed/strengthened
  • (Higgs properties measurements/Heavy Higgs
    production)
  • Must do appropriate RD to keep the possibility
    of a PC

3
Studies Reach Maturity
  • Aim Level of detail in ?? as good or better than
    in ee-
  • SIMDET simulation (ee- detector/ see K.
    Moenig). Brahms?
  • Real Luminosity spectra/polarization used
  • B search using ZVTOP
  • Adding overlap events
  • QCD backgrounds in NLO
  • QCD Monte Carlo tuning to existing data
  • Cross checks for key processes (Higgs production)
  • Direct contact exchange with the NLC
    studies/exchange tools
  • More work still needed on
  • Luminosity/polarisation measurement (
    corresponding syst.)
  • Final design of IP/vertex detectors (?
    backgrounds)

4
AMEGIC for ??
S. Schumann, F. Kraus
Event generator AMEGIC
Resolved Direct
5
AMEGIC for ??
Matching ME to parton showers NLO
Underlying event structure Hadronization and
fragmentation Specific for ?? Photon
decomposition structure
Expect first version (for lepton final states)
next month/ Hadrons early next year. !Useful for
background studies to Higgs!
6
Monte Carlo Tuning
M.Wing
fit MC parameters to data from LEP, HERA
Tevatron
JetWeb hep-ph/0210404 http//jetweb.hep.uc
l.ac.uk J Butterworth et al
7
MC Tuning
? have to check effects on our backgrounds
8
(No Transcript)
9
SM Higgs analyses
  • UpdateUse SIMDET ZVTOP B finder

P. Niezurawski
81 1.8
10
SM Higgs analyses
1 year/84 fb-1
Systematics??
Using NLO backgrounds (Jikia) Fragmentation
questions?
11
SM Higgs analyses
A. Rosca
Pythia reweighted with NLO cross sections ZVTOP
Tagging optimization still ongoing (presently
lower than prev. analysis)
12
Overlap events
  • 1.5 central high energy ?? events for L??(z gt
    0.8zmax)
  • 1.1 .1034 cm-2 s-1
  • Files for TESLA have been prepared/SIMDET adapted
    to use overlays
  • ee- and ??
    files
  • So far catalogued on the CLIC page
  • //clicphysics.web.cern.ch/CLICphysics
  • 200 500 GeV files available ??
    file contains 5000 events
  • Selection events W2 gt 5 GeV2 ,
  • tracks Ptgt 150 MeV,
  • ? gt 80 mrad
  • photon polarization not taken into account

Effect on the measurement? Work in progress
13
SM Higgs analyses
14
H/A Higgs
D. Asner/J. Gunion (LCWS02) Need few years to
Close the wedge Need also European study
15
Low Mass Charged Higgs
V. Martin
Using H ??? decays Full simulation
Relative low efficiency after cuts 2.5
What can a PC contribute?
16
2HDM model
M. Krawczyk
17
Upcoming initiative
M. Krawczyk R. Godbole
Invitation
18
CP studies via ?????tt
R. Godbole et al. hep-ph/021136
LCWS02 Construct combined asymmetries
from intial lepton polarization and decay lepton
charge Done with realistic spectra etc., but
needs study with simulation
19
Trilinear Gauge couplings in e?
D. Anipko
Analyse d2?/dp dcos??e CompHEP
20
Trilinear Gauge couplings in e?
J Sekaric K. Moenig
  • Fitting results of the fit of ?? and ?? for 1
    photon polarization state single and two
    parameter fit for real (e? ) mode

REAL MODE 1 par. fit ECM 450 GeV, L 110 fb-1 ECM 450 GeV, L 110 fb-1 ECM 450 GeV, L 110 fb-1 ECM 450 GeV, L 110 fb-1 ECM 450 GeV, L 110 fb-1 ECM 450 GeV, L 110 fb-1
REAL MODE 1 par. fit J? 1 J? 1 J? 1 J? -1 J? -1 J? -1
?L 1 0.1 accur. 1 0.1 accur.
??? 10-3 3.4 1.0 0.5 9.7 1.1 0.5
??? 10-3 1.6 1.5 1.5 4.6 4.4 3.8
2 par. fit
??? 10-3 5.1 1.1 0.5 9.7 1.1 0.6
??? 10-3 2.3 1.6 1.6 4.6 4.6 4.6
  • REAL MODE - pure e?-mode, known beam directions

e? ?W? , hadronic decay channel/total and
differential cross sections
21
  • comparison of the single parameter fit for e? ,
  • ?? -, and e-e - colliders

Ee? 450 GeV L110 fb-1 E?? 400 GeV L110 fb-1 Eee 500 GeV L500 fb-1
?L 0.1 0.1
???10-4 10 / 9.8 6.7 3.1
???10-4 15 / 5.8 6.0 4.3
  • sensitivity to ?WW only! - ??? ,??? 10-3

22
Most important processes
hep-ph/0103090
  • ?? ? ?
  • ? ? ?
  • ? ? ?

Higgs
Susy
Tril/quart.
Top
QCD
Added since then Non-commutative measurements,
? e? for EDs, Light gravitinos, Radions, ?
H????, ? H?HH-?
  • Being done/ready
  • promised

Any Volunteers??
23
Plans
  • Finalize current analyses, particularly higgs
    sector
  • If IP studies in near future will require
    changes? need to know this asap
  • High priority to start H/A SUSY particle
    analysis, CP studies
  • Use synergy with NLC group/exchange of tools
  • Indian group starts studying EDs in ?? and e?
    (R. Godbole et al.). Expect first results by
    Amsterdam
  • Additional meeting before Amsterdam
  • February 13 _at_ CERN
  • Plan to write up summary of the PC studies for
    Amsterdam
  • At Amsterdam Plan a panel discussion on a PC
    collider

24
NLC studies overview
25
D. Miller Determining the Spin of the H in ??
collisions
26
H/A higgs
Can a photon collider close the wedge? Cross
section gets small For M(H/A) gt 600
GeV J.Gunion 2-4 years needed CP studies
Expect need to run of photon collider for
several years if the physics scenario warrants
it!
27
Luminosity and spectra
Usable in event simulation (Telnov/Ohl/Zarnecki) P
andora
For TESLA
ZW??/2Ebeam
28
Cross sections
29
B-tagging
  • Reconstruction of the vertex using a topological
    vertex technique (ZVTOP).

IP
Primary vertex Secondary vertex Tertiary
vertex
B
D
30
The photon collider case
  • Advantages
  • Large cross sections (e.g. WW production cactor
    20-40 times)
  • Large circular polarization e-e- beams (80) ? ?
    (90-95 in peak)
  • Linear polarization (CP filter)
  • Extended kinematic range for some new particles
  • S-channel production for H, /association e.g.
    slepton ? lepton?0
  • Sometimes different couplings probed (no Z
    effects)
  • Issues
  • Luminosity spectrum spread (not monochromatic,
    but much better than LHC). How precise can we
    measure the spectrum/luminosity?
  • Luminosity typically factor 3 lower compared to
    ee-(but yet not at limit)
  • Needs RD to proof it works as expected. ? plans
  • More complicated IR
  • Debate of backgrounds and its implication on
    detector not yet finalized
  • Only few processes so far studied in (almost) all
    experimental details, most important one ?? ?
    Higgs

31
The light Higgs
State of the art (M. Krawczyk)
All background under control? B-tagging different
in ???
32
Background studies
Frequently asked question same b-tagging
efficiency as in ee- case?
K. Moenig et al. backgrounds studied for TESLA
IP layout
Study beam related background of hits in the
layers of the pixel Detector per bunch
crossing Incoherent pair production
essentially the same as for ee- Coherent pair
production under study Neutrons? Will be able
to answer this question soon
33
Is a photon collider a hadron collider?
NO !
  • The QCD background in a ?? collider can be large
  • Eg. for Lgeom 1035 cm-2 s-1, 400 nb ??
    cross section
  • ? 3 ?? events/bunch
    crossing
  • Many events boosted and/or low mass no problems
  • V. Telnov (TESLA TDR appendix) 1.5 central high
    energy ?? events
  • for L??(z gt 0.8zmax) 1.1 .1034 cm-2 s-1

of jets (Et gt 5 GeV)
10-20 tracks/event ltETgt few GeV, tails up to
20-30 GeV Looks not so bad! (ADR, ST Malo
meeting) Common study with theorists and NLC
groups starting
? gt 80 mrad
? gt 250 mrad
34
RD program
Europe RD for lasers in IP (10 size prototype
cavity planned) US Laser development at LLNL
Plan for SLC photon collider testbed at
SLAC (means reactiviating SLC/ Workshop
at SLAC Nov 21-23 02
Conclusion Photon collider will enrich the
program of an ee- machine We
cannot afford NOT to study it !
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