Higgs boson pair productions in the Georgi-Machacek model at the LHC

Higgs bosons pair production is well known for its sensitivity to probing the sign and size of Higgs boson self coupling, providing a way to determine whether there is an extended Higgs sector. The Georgi-Machacek (GM) model extends the Standard Model (SM) with an SU(2)_L triplet scalar field that has one real and one complex components. The Higgs self coupling now has a wider range than that in the SM, with even the possibility of a sign flip. The new heavy singlet Higgs boson H₁ ⁰ can contribute to s-channel production of the hh pairs. In this work, we study non-resonant/resonant Higgs boson pair productions pp → hh and pp → H₁ ⁰ → hh, focusing exclusively on the contribution of H₁ ⁰. We show the sensitivity for Higgs boson pair production searches at the 13-TeV LHC with the luminosities of 3.2, 30 and 100 fb⁻¹.