Background studies and spin correlation expectations in $t \bar t$ events in the $e\mu$ decay channel at the LHC

One of the many interesting features of the top quark is its extraordinarily short lifetime. One consequence of this short lifetime is that the spin information of a decaying top quark is inherited by the decay products. Thus the spin information of the decaying top-antitop pairs can be extracted by examining the final state particles. A requisite step in such an analysis is the selection of a clean sample of $t\bar t \rightarrow e\mu$ events and this can be done by a careful examination of the background processes. We lay out a cut based method to enhance the signal versus the background in $t\bar t$ events in the $e\mu$ decay channel using Monte Carlo events and we also map out a method to investigate $t\bar t$ spin correlation at the ATLAS experiment at the LHC.