tt¯bb¯ as a probe of new physics at the LHC

Abstract

We study the ttbb final state at the LHC as a probe of new physics that couples mainly to the third generation of quarks. We analyze new physics simplified models with resonances of spin-0, -1 and -2. The sensitivity of the final states ttbb, tttt, bbbb and tt on each of these models is used to identify an important region in parameter space that is still not excluded and where ttbb is the most sensitive final state. We indicate possible experimental hints and discuss potential issues of observables that rely mainly on Monte Carlo predictions. A new observable is proposed that, at the price of requiring more statistics, reduces the impact of Monte Carlo predictions. We use preliminary 13 TeV results to give a raw estimate on the discovery reach and propose simple improvements on the observables.