Boosting Higgs Pair Production in the $b \bar b b \bar b$ Final State at the HL-LHC with Multivariate Techniques

In this contribution we present a new strategy for measuring Higgs pair production in the b ̄ bb ̄ b final state at the Large Hadron Collider (LHC) and its future high-luminosity upgrade, the HL- LHC. This process is of particular interest as it allows for the extraction of the Higgs trilinear coupling and therefore provides a crucial test of electroweak symmetry breaking. Moreover, it is sensitive to effects of physics beyond the Standard Model. The measurement of Higgs pair pro- duction is therefore considered one of the key goals of LHC physics programme. In our analysis, we take into account all possible Higgs decay topologies to provide optimal sensitivity over a large kinematic range. Our analysis combines a traditional cut-based approach with multivariate analysis techniques and has been shown to be robust in a high pile-up environment. All relevant backgrounds are taken into account, including the 2 b 2 j component of QCD multi-jet production, which yields a non-negligible contribution due to light- and charm-quark jet mis-identification. We obtain a signal significance of S / B ' 3 for an integrated luminosity of L = 3 ab − 1 and show that, pending various experimental improvements, the b ̄ bb ̄ b final state alone may allow for the observation of Higgs pair production at the HL-LHC.