The non-resonant and resonant Higgs pair production at the HL-LHC

Direct measurement of the Higgs self-coupling is crucial to understanding the nature of electroweak symmetry breaking, which requires observation of Higgs pair production. We study the prospects of observing the non-resonant Higgs pair production at the high luminosity run of the 14 TeV LHC (HL-LHC) upon considering various di-Higgs final states. A search is also performed for the heavy resonant scalars ($H/A$) via their decay into SM final states at the HL-LHC. We set upper limits on the production cross-section of heavy scalar times its branching ratio into final state products for different heavy scalar masses. Finally, we translate these limits and put constraints on the $m_A-\tan\beta$ parameter space in the context of the Minimal Supersymmetric Standard Model (MSSM).