ttbar resonance searches in the lepton plus jets topology using 200 pb-1 of pp collisions at $\sqrt {s} $ =7 TeV in ATLAS

Abstract : The top quark is the heaviest elementary particle known. Some Beyond Standard Model theories predict the existence of new heavy particles decaying into top pairs. In the lepton plus jets topology the search of these resonances is done using the tt bar mass spectra, which is built by three or four jets, an electron or muon and a neutrino. The benchmark model used to quantify the experimental sensitivity to narrow resonances is a leptophobic Z0 boson arising in models of strong electroweak symmetry breaking through top quark condensation [1]. The model used for wide resonances is a Kaluza-Klein gluon gKK, which appears in Randall-Sundrum (RS) models with a warped extra dimension.