Jet substructure reconstruction and application as a search tool for new physics in the ATLAS experiment at the LHC
by
DrPeter Loch(University of Arizona, Tucson)
→
Europe/Berlin
Auditorium (MPI fuer Physik)
Auditorium
MPI fuer Physik
Description
The proton-proton collisions at the Large Hadron Collider
(LHC) at CERN, Geneva, Switzerland, at center of mass energies
of sqrt(s) = 7 TeV and sqrt(s) = 8 TeV in 2011 and 2012,
respectively, allow the exploration of previously unreachable
kinematical regimes, where potentially new heavy particles can
be produced with a significant momentum boost. Several models for
these particles suggest collimated all hadronic two- or three-prong
decays, with the decay products presenting themselves within a cone
in rapidity and azimuth space, similar to particle jets generated
by the fragmentation of light and heavy quarks, and gluons. In recent
years a suite of jet substructure reconstruction techniques has been
developed. Basically all of them exploit the observable differences
in the internal structure of the boosted object jets, which reflect
the particular decay pattern, with respect to the quark and gluon
initiated (QCD) jets, which are generated by the parton shower and
radiation driven particle flow. The efficiency of the individual
techniques in determining the source for the jet is important for
new particle searches and is presently evaluated using known boosted
particle signatures like the hadronically decaying boosted W-boson
and top quark. In this talk the most promising substructure
reconstruction techniques are presented with respect to their
performance in the experimental environment of the 2011 and 2012
data taking with the ATLAS detector at the LHC. Experimental results
for substructure observables are discussed in the context of the
increasing pile-up from additional proton-proton collisions in the
same LHC bunch crossing as the triggered hard scatter event. The
application of the substructure techniques in the reconstruction of
the full hadronic top quark decay is shown, and the application of
these techniques in selected searches is presented.
