Dominant production of heavier Higgs bosons through vector boson fusion in NMSSM

We study the features of the additional Higgs bosons in the Next-to-Minimal Supersymmetric Standard Model where the lightest beyond Standard Model Higgs boson does not dominantly couple to up-type quarks. The new state is dominantly singlet-like while it can also accommodate a small down-type Higgs component. The gluon-gluon fusion cannot be adequate enough for such a Higgs production. We show that the vector-boson fusion may become the leading production mechanism to probe this new scalar at the LHC. Using the existing 13 TeV LHC data for an integrated luminosity $36.1~fb^{-1}$, we show the LHC constraints on the parameter space. Finally, we also study the reach of the planned high luminosity LHC (${\mathcal L}=3~{\rm ab}^{-1}$ at $\sqrt s=$~14 TeV) and the proposed high energy upgrade of the LHC (${\mathcal L}=15~{\rm ab}^{-1}$ at $\sqrt s=$~27 TeV) to probe this singlet-like Higgs scalar.