Transcript Java Physics Generator and Analysis Modules Mike Ronan LBNL

Java Physics Generator and
Analysis Modules
Mike Ronan
LBNL
(presented by Tony Johnson)
Goals
• Disparate groups working worldwide on Linear
Collider physics studies have produced
complementary tools using a variety of
languages and methodologies
• From a physics perspective it is desirable to
directly compare the results from these different
tools
• A framework for accessing different modules in a
uniform way has been developed, allowing one
analysis module to be used with all tools
– Methodology not specific to linear collider studies
Methodology
• Use Java for building framework:
– Good OO language for rapid development of analysis
algorithms
– Use Java Native Interface (JNI) to call different
language modules and retrieve results back into Java
objects
– Adapt each tool to use common java interfaces
• E.g. All generators create same HEPevt
– Use existing Java analysis tools for data analysis
• JAS, JAIDA, etc.
• US Linear Collider physics tools (Java)
– 3,4 vector tools, jet finders, vertex finding, etc.
– Provide access to Java based scripting languages
• jython, pnuts, dynamic java etc.
Event Generators Interfaced
• Pandora-Pythia V2.2 Monte Carlo using
PanoraPythia interface package
– C++ and Fortran 77
• Pythia v6.2 Monte Carlo with Circe
beamstrahlung simulation
– Fortran 77
• Whizard V1.22 Monte Carlo with ISR and
Circe turned on
– Fortran 95
Implementation
• Use Java native Interface (JNI)
– For interfacing to generators only need to implement a
few methods
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setParameter() setProcess()
init()
generateEvent()
getEvent() – Access to HEPEvt, common to most generators
finish()
– Infrastructure can be reused with little change between
generators
– Use standard tools (gmake etc.) to build .so file
• Other libraries (i.e. CERNLIB) can be statically linked into .so
file
– Rarely needs to be rebuilt
• All interactive work can be done in Java
Usage Example
• Details of how to set up generator varies from
generator to generator
– All follow same basic pattern
– All generate same set of Java objects representing
generated particles
More about HEPEvt classes
Java Object Model
HEPEVT
Common Block
HEPEvt
Particle
ParticleType
Pandora, Pythia, Whizard
Comparisons
• FMCParticle jet
distributions
– Number of “correctly”
reconstructed jets
– Angular distribution
(CosθMax) of jets
– Jet finder final “ycut”
– Direct reconstruction of Z
and Higgs through
hadronic decays.
• Good agreement
between Pandora, Pythia
and Whizard simulation
Simulation Packages
• LCD Fast Monte Carlo v1.4 (Java)
– Charged particle momentum smearing based on detailed error
estimates
– Gaussian energy smearing for photons and neutral hadrons
– Acceptance and energy threshold requirements
– Perfect energy flow
• TESLA SimDet V4.0 (Fortran 77)
– Parameterized charged and neutral energy smearing based on full
(Brahms) Monte Carlo simulations
– Acceptance requirements
– A new energy flow algorithm
• JLC QuickSim V2.1 includes (C++)
– Charged particle momentum and position smearing based on detailed
error estimates
– Simulation of individual calorimeter cell hits and cluster finding
– Track-cluster association to separate charged and neutral clusters
Interoperability
Pythia
Pandora
LCD FastMC
Event
Selection
Whizard
Event Generators
TESLA
SimDet
JLC
QuickSim
Java
Fortran
C, C++
Detector
Simulation
Analysis
Code
US FastMC, SimDet & QuickSim
Detector Simulations
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Direct reconstruction of Z and Higgs through hadronic decays is shown for Higgstrahlung signal events only. Jet-jet
mass distributions for US FastMC, TESLA SimDet and JLC QuickSim detector simulations are reconstructed for
Whizard-MadGraph Monte Carlo events including ISR and Circe beamstrahlung effects.
The LCD FastMC jet-jet mass resolution is significantly better since it assumes “perfect” energy flow. TESLA SimDet
and JLC QuickSim detector simulations give comparable jet energy resolutions but different mean reconstructed jetjet masses.
Whizzard: MadGraph
Higgstrahlung Event Analysis
Conclusions and Future
• Hand coded JNI solutions works well for interfacing to
event generators, simple simulation programs
– Brings advantages of Java based analysis to Fortran and C,C++
code
– Allows direct physics comparisons of disparate tools
• New tools are now available which will make this approach
more scalable
– JACE http://reyelts.dyndns.org:8080/jace/
• Integration with gcc-xml, or POOL dictionary?
– Web/Grid services
– LCIO – Common IO system for international linear collider studies
• see talk by Frank Gaede at this conference)
• All tools used in this study available from:
– http://www.lbl.gov/~ronan/docs/lcdstudies/
Higgstrahlung