Title:

Study of an electron-muon resonance in a R-parity violating supersymmetric
model using ATLFAST-II

Thesis abstract:

Supersymmetry (SUSY) is one of the best theoretically motivated beyond the
Standard Model (BSM) scenarios, and a favored candidate to be discovered
by the experiments at the Large Hadron Collider (LHC). The ATLAS
collaboration has been extensively searching for SUSY signatures using
2010, 2011 and 2012 data from LHC proton-proton collisions at a
center-of-mass energy of 7 TeV and recently at 8 TeV. However, so far no
signs of SUSY or any other BSM physics has been found.

In absence of the real data measured by the detector, the Monte Carlo
simulation provides a way to design new physics analyses and quantify
expected detector performance. The constraints on SUSY models are one of
the main reasons for the production of a large number of Monte Carlo
simulated samples, as there is the need to increase the
analyses sensitivity to more challenging topologies. The simulation of a
large number of Monte Carlo samples represents a big challenge in terms of
central processing unit (CPU) time consumption and end-user waiting time.
Then, it is of extreme importance to find a fast and accurate way to
simulate SUSY signal samples. The ATLAS collaboration has been developing
a fast simulation package: ATLFast-II, where the above mentioned times are
significantly reduced. However, the use of ATLFast-II for signal
sample production must be evaluated in a case by case basis and its use is
justified only when there is no loss of accuracy in simulating physics
objects.

The current work investigates the performance of ATLFast-II in a
particular R-parity violating (RPV) SUSY model predicting the existence of
a heavy neutral short-lived resonance (a tau sneutrino) that decays to an
electron-muon pair with opposite charges. It is the first dedicated
study of the performance of ATLFast-II using a RPV SUSY model.