Mainz 2014 – scientific programme

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T: Fachverband Teilchenphysik

T 14: Top-Quarks: Boosted

T 14.1: Talk

Monday, March 24, 2014, 11:00–11:15, P102

Validation of AtlFastII for Jet Substructure — •David Sosa, Sebastian Schätzel, and André Schöning — Physikalisches Institut, Universität Heidelberg

The AtlFastII (AFII) software performs a fast simulation of the calorimeter using parametrised showers whereas the full simulation employs GEANT to trace the path and interactions of all incident and secondary particles. The use of the fast simulation is desirable to speed up the turnaround time for studies of systematic uncertainties and data analysis.

For the analyses of boosted heavy particles, such as top quarks, vector bosons, and Higgs bosons, the performance of AFII in describing jet substructure variables is evaluated. A sample of boosted top quarks obtained from the ATLAS 2012 data with the HEPTopTagger is compared with the fast and full simulations of Monte Carlo generated events.

The hard jet substructure is found to be well described whereas discrepancies are observed between fast simulation and data for variables that are sensitive to low energy particles. The impact of changes in the AFII parameterisations to improve the description of jet substructure variables is investigated.