Preliminary study for $t\bar{t}$ resonance search in dilepton channel and performance of muon reconstruction close to jets in ATLAS

A preliminary study on a search for resonances decaying to t ¯ t in the dileptonchannel is presented. From these decays, the spin-correlation information isexploited in order to search for physics phenomena. A preliminary check usingsimulated samples has been done. Moreover, a study on the reconstructionefficiencies for muons close to jets, useful for high-m t ¯ t invariant mass ispresented. The first reconstruction efficiencies for muons close to jets in theATLAS detector are also presented in this article.