  We explore the four top signal ttbar ttbar at the 7 TeV Large Hadron Collider
as a probe of physics beyond the standard model. Enhancement of the
corresponding cross-section with respect to the Standard Model value can probe
the electroweak symmetry breaking sector or test extra dimensional models with
heavy Kaluza-Klein gluons and quarks. We perform a detailed analysis including
background and detector simulation in the specific case of a universal
extra-dimensional model with two extra dimensions compactified using the
geometry of the real projective plane. For masses around 600 GeV, a discovery
is possible for an effective cross section above 210 fb (36 fb) for 1/fb
(10/fb) of integrated luminosity. This implies a branching ratio in tops of the
(1,1) heavy photon above 13% (5%). Furthermore, the 4-top signal from the (2,0)
and (0,2) tiers can be discovered with an integrated luminosity of 3.5/fb. The
results of our simulation can be easily adapted to other models since the
background processes are identical. Concerning the signal, typical production
mechanisms for the ttbar ttbar signal are similar even if cross-section values
may vary considerably depending on the model and the spectrum of the new
particles.
