Search for Higgs boson pair production in the b anti bτ⁺τ^- final state with the ATLAS detector

In the Standard Model (SM) Higgs bosons can be produced in pairs via top loops or the Higgs trilinear self-interaction. Although the SM cross-section for Higgs pair production is very small and impossible to measure with the data currently collected at the LHC, in several extensions of the SM this cross-section can be enhanced. Non-resonant Higgs pair production can be significantly enhanced by modifications of the triple Higgs self-coupling λ_hhh. Other theories predict heavy resonances that could decay into a pair of Higgs bosons with m=125 GeV, such as a neutral scalar heavy Higgs in the two Higgs doublet model and spin-2 Kaluza-Klein excitations of the graviton in the bulk Randall-Sundrum model. In the assumption of Higgs bosons with m=125 GeV decaying with branching fractions according to the SM predictions, the b anti bτ⁺τ^- channel of the di-Higgs decay has the third largest branching fraction (7.4%) and it is relatively clean compared to channels with larger branching fractions but also larger backgrounds. The search for resonant and non-resonant pair production of Higgs bosons in the b anti bτ⁺τ^- final state with the ATLAS detector and its latest results will be presented in this talk, with particular focus on the development of an MVA for improving the analysis sensitivity.