NLO matching for tt¯bb¯ production with massive b-quarks

Theoretical uncertainties in the simulation of tt¯bb¯ production represent one of the main obstacles that still hamper the observation of Higgs-boson production in association with top-quark pairs in the H→bb¯ channel. In this Letter we present a next-to-leading order (NLO) simulation of tt¯bb¯ production with massive b-quarks matched to the Sherpa parton shower. This allows one to extend NLO predictions to arbitrary tt¯bb¯ kinematics, including the case where one or both b-jets arise from collinear g→bb¯ splittings. We find that this splitting mechanism plays an important role for the tt¯H(bb¯) analysis.