Benchmarks for Double Higgs Production in the Singlet Extended Standard Model at the LHC

The simplest extension of the Standard Model is to add a gauge singlet scalar, $S$: the singlet extended Standard Model. In the absence of a $Z_2$ symmetry $Srightarrow -S$ and if the new scalar is sufficiently heavy, this model can lead to resonant double Higgs production, significantly increasing the production rate over the Standard Model prediction. While searches for this signal are being performed, it is important to have benchmark points and models with which to compare the experimental results. In this paper we determine these benchmarks by maximizing the double Higgs production rate at the LHC in the singlet extended Standard Model. We find that, within current constraints, the branching ratio of the new scalar into two Standard Model-like Higgs bosons can be upwards of $0.76$, and the double Higgs rate can be increased upwards of 30 times the Standard Model prediction.