Speaker
Please give a brief summary of your poster
Tau leptons, and particularly their hadronic decays, will play an
important role at the LHC. They will not only be invaluable for
understanding the performance of the ATLAS detector but will also be
of great importance in searches for the Higgs Boson and supersymmetric
particles.
A key component of the overall tau selection is the tau trigger, which
will provide a rejection of 10^6 against low-energy jets and an
overall efficiency of 80% with respect to hadronic tau leptons
identified by the offline algorithms. In the initial running it will
be used standalone for high energy items (typically for $E_T$ above 60
GeV) and in combination with missing $E_T$, electrons, muons or jets
for lower $E_T$ values.
Several offline identification strategies are being developed, some of
them using advanced multivariate techniques. The commissioning of both
trigger and identification algorithms has started with cosmics and
first beam data.
Feasibility studies for analyses which can be envisaged with an
integrated luminosity of 100 pb$^{-1}$ are presented. W->tau nu events
will provide the first relatively clean sample of tau leptons,
allowing studies of the performance of the tau trigger and
identification. Z->tau tau events with one tau decaying leptonically
and one hadronically will help to understand efficiencies of the tau
trigger, identification and mis-tagging. In addition they will allow
for the in-situ determination of the tau energy scale and of the
missing transverse energy scale. Events from ttbar processes with one
W decaying to a tau lepton will be used to understand the
reconstruction and identification performance of taus in a busier
environment, more relevant to the future discovery physics program in
ATLAS.
