Signals from R-parity violating top quark decays at LHC

We evaluate the potential of the CERN LHC collider to observe rare decays ofthe top quark in channels involving R-parity violating (RPV) interactions. Westress the importance of calculating top quark production and decaysimultaneously as a true 2->4 process. The process of tt-bar pair production followed by RPV decay of one of the topquarks is analyzed with fast detector simulation. We show that intermediatesupersymmetric particles can be observed as resonances even if they are heavierthan the top quark due to the significant off-shell top-quark mass effects. Theapproach where the top quark is produced on-mass-shell and then decays into 2-or 3-body final state would in general lead to incorrect kinematicaldistributions and rates. The rates of the 2 -> 4 process with top quarkproduction and RPV 3-body decay depend on the total width of the heavyintermediate sfermion which could,therefore, be measured indirectly. We find that the LHC collider offers a unique potential to study rare topquark decays in the framework of supersymmetry with broken R-parity forbranching fractions of RPV top decays as low as 10^{-6}Comment: 23 pages, 22 figure