FrancoRussia Forum

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Particle Physics and Simulation

• ACPP
• Automated Calculation in Particle Physics
• France-Japan-Russia collaboration

Denis Perret-Gallix CNRS
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Matter and Forces
The standard model
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Unsolved Mysteries
Why do we see matter and almost no anti-matter?
CP violation Belle- Babar exp.
Why the  standard model does not predict the
mass ?
The Higgs Particle ?
What is this  dark matter  that we cannot see
but has visible gravitational effects?
Why the neutrino mass is so small?
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Unsolved Mysteries
Are quarks and leptons actually fundamental, or
made up of even more fundamental particles?
Why are there exactly three generations of quarks
and leptons?
How does gravity fit into all of this?
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Beyond the Standard Model
Supersymmetry
M-theory and extra-dimensions
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Particle Physics Pure Knowledge Research
Ultimate Quest The Theory of Everything
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A highly Experimental and Technical Research
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LHC at CERN
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A World-Wide Endeavour
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Astro-particles Cosmology
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WMAP results
Universe expansion speeds up
WMAP Photon temperature 2.73K

• 70 dark energy
• 25 dark matter
• 5 matter and radiation

Comological constant anti-gravity Einstein  My
biggest mistake 
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Experiment Simulation

• A Mandatory Component of HEP experiments

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Looking for Higgs
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Simulation and data Analysis
Physics Model
Nature
Process
Event simulation
Event Generator
Event E/P Quadri-vectors
Detectors Simulation
Detectors
Event Hits, Energies, Timing
Event Hits, Energies, Timing
Reconstruction
Comparison
Event E/P Quadri-vectors
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No detector design no results without simulation
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Event simulationat LHC
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Hadron collider Physics
Hadronization
b
c
s-
Heavy Quarks
W
u-
d
Parton shower
W-
?10
?10
t
t-
?1-
u
t-
u
Hard sub-process
g
u
g
Multiple interaction/underlying event
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Feynman diagrams
Interaction Computation
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Higher order calculations
H ? t b at first order 1
at 1-loop 97 diagrams
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What is automatic calculation?

• It is now impossible to perform
• accurate theoretical calculations
• by hand for collider experiments.

?Increasing the requested accuracyat LHC 10
at ILC 0.1 Radiative Corrections LHC
100,LC 10 ?Tree is not adequate.
Need higher order corrections!! ?
Multi-particle productions ?increasing
the number of diagrams.
J. Fujimoto
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An International Collaboration
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International Research GroupACPP Automated
Calculation in Particle Physics

• 48 physicists from France, Russia, Japan
• Russia Lomonosov Moscow State Univ.(14),
  Russian Academy of Science(2)
• Japan KEK Minami-Tateya collaboration(19)
• France CNRS(9), Univ. de Savoie, Clermont 2(1),
  Montpellier 2(2), Paris. 11(1)
• Main packages Grace, Grace 1-L (28 pub),
  CompHEP, LanHEP, CalcHEP (30 Pub)
• For LHC, ILC, Astro-Particle PhysicsGRC4F (147
  cit.), micrOMEGAs,

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Grace Package(Japan)
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Comphep Package (Russia)
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Applications LEP, B-factory, LHC, ILC, Cosmology
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LEP II GRC4Fa 4-fermion event generator for
ee- collisions

• Tree level helicity amplitudes produced by
  GRACE http//www-sc.kek.jp/minami/
• Fermion mass and full spin correlations included
• 76 4-fermion final states processes gt2500 diag.
• ISR, FSR, Beamstrahlung
• Interface to Parton showers and hadronization
  (Pythia)
• Anomalous couplings
• hep-ph/9605312, Comp. Phys. Comm 100128-156

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Radiative Corrections to Higgs processes by
GRACE International Linear Collider
J. Fujimoto
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hep-ph/0307029Phys.Lett.B 571(2003) 163.
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micrOMEGAs LAPP-Moscow
The relic density of Dark Matter in
supersymmetry 2800 tree level processes (CalcHEP)

• WMAP data put constraints on the Susy parametres
• LHC/ILC put constraint on Omega

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Automatic Calculations in Particle PhysicsACPP

• Mandatory for experiment designs and data
  interpretation
• A perfect case for International collaboration
• A pluridisciplinary program Theory, Computing
  and experiments
• Very active collaboration
• AIHEP/ACAT workshops (Advanced Computing and
  Analysis Techniques)
• Les Houches workshops

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Automatic Calculations in Particle PhysicsACPP
Future
Higher precision predictions are required by
coming projects LHC, ILC, super-B factory,
Planck,

• Theory developments for 1-loop, 2-loop processes
• Better interface with experiments
  (Standardization,)
• Large computing power
• Efficient symbolic manipulation package
• Singularity tolerant numerical integration
  algorithm
• High precision floating point calculation
  (quadruple/octuple precision)
• High performance parallel/farm systems