Speaker
Dr
Steffen G. Kappler
(III. Physikalisches Institut, RWTH Aachen university (Germany))
Description
Physics analyses at modern collider experiments enter a new dimension of event
complexity. At the LHC, for instance, physics events will consist of the final state
products of the order of 20 simultaneous collisions. In addition, a number of today’s
physics questions is studied in channels with complex event topologies and
configuration ambiguities occurring during event analysis.
The Physics Analysis eXpert toolkit (PAX) is a continuously maintained and advanced
C++ class collection, specially designed to assist physicists in the analysis of
complex scattering processes. PAX allows definition of an abstraction layer beyond
detector reconstruction by providing a generalized, persistent HEP event container
with three types of physics objects (particles, vertices and collisions), relation
management and file I/O scheme. The PAX event container is capable of storing the
complete information of multi-collision events (including decay trees with spatial
vertex information, four-momenta as well as additional reconstruction data). An
automated copy functionality for the event container allows the analyst to
consistently duplicate event containers for hypothesis evolution, including its
physics objects and relations. PAX physics objects can hold pointers to an arbitrary
number of instances of arbitrary C++ classes, allowing the analyst to keep track of
the data origin within the detector reconstruction software. Further advantages
arising from the usage of the PAX toolkit are a unified data model and nomenclature,
and therefore increased code lucidity and more efficient team work. The application
of the generalized event container provides desirable side-effects, such as
protection of the physics analysis code from changes in the underlying software
packages and avoidance of code duplication by the possibility of applying the same
analysis code to various levels of input data.
We summarize basic concepts and class structure of the PAX toolkit, and report about
the developments made for the recent release version (2.00.10). Finally, we present
advanced applications of the PAX toolkit, as in use at searches and physics analyses
at Tevatron and LHC.
Summary
References:
[1] M. Erdmann et al., Physics Analysis Expert PAX: First Applications, Proceedings
of the 2003 Computing in High Energy and Nuclear Physics conference (CHEP03), La
Jolla, Ca, USA, March 2003.
[2] Martin Erdmann et al., New Applications of PAX in Physics Analyses at Hadron
Colliders, Proceedings of the 2004 Computing in High Energy and Nuclear
Physics conference (CHEP04), Interlaken, Switzerland, September 2004.
[3] Steffen Kappler et al., The PAX Toolkit and its Applications at Tevatron and
LHC, accepted by IEEE Trans. Nucl. Sci., 2005.
[4] Project webpage: http://www.cern.ch/pax
Primary author
Dr
Steffen G. Kappler
(III. Physikalisches Institut, RWTH Aachen university (Germany))
Co-authors
Mr
Alexander Schmidt
(Institut f. Exp. Kernphysik, Karlsruhe university (Germany))
Prof.
Günter Quast
(Institut f. Exp. Kernphysik, Karlsruhe university (Germany))
Mrs
Joanna Weng
(CERN & Institut f. Exp. Kernphysik, Karlsruhe university (Germany))
Prof.
Martin Erdmann
(III. Physikalisches Institut, RWTH Aachen university (Germany))
Mr
Matthias Kirsch
(III. Physikalisches Institut, RWTH Aachen university (Germany))
Mr
Ulrich Felzmann
(Institut f. Exp. Kernphysik, Karlsruhe university (Germany))
