A search for pairs of Higgs bosons in the $b\overline{b}$${\tau }^{+}{\tau }^{-}$ decay channel with the ATLAS detector

After the discovery of the Higgs boson, a full measurement of the Higgs potential is needed to further probe the mechanism of electroweak symmetry breaking. Since the Higgs potential is related to the fact that the Higgs boson couples to itself, such a measurement can be performed by searching for pairs of Higgs bosons. However, the Standard Model (SM) predicted cross-section is very small due to destructive interference between the Higgs self-coupling and the Higgs-fermion Yukawa coupling production modes. On the other hand, a search for pairs of Higgs bosons potentially offers insight into physics beyond the Standard Model (BSM), since several BSM hypotheses predict heavy resonances that could decay to a pair of Higgs bosons. A search for non-resonant and resonant Higgs boson pair production in the $b\overline{b}$${\tau }^{+}{\tau }^{-}$ channel is presented for 36.1 fb${}^{-1}$ of $\sqrt{s}$ = 13 TeV data taken by the ATLAS experiment at the Large Hadron Collider (LHC). The analysis considers the semi-leptonic and fully hadronic di-tau final states. The $b\overline{b}$${\tau }^{+}{\tau }^{-}$ final state is one of the most sensitive channels and, in particular, it is the most sensitive channel to search for non-resonant Higgs boson pair production. A study on the High-Luminosity Large Hadron Collider (HL-LHC) prospects of the SM Higgs pair production in the $b\overline{b}$${\tau }^{+}{\tau }^{-}$ channel is also presented in addition.