  Extensions of the Standard Model Higgs sector with electroweak charged
scalars can possess exotic `Higgs' bosons with vanishing or suppressed
couplings to Standard Model fermions. These `fermiophobic' scalars, which
cannot be produced via gluon fusion, are constrained by LHC measurements of the
125 GeV Higgs boson to have a small vacuum expectation value. This implies that
vector boson fusion and associated vector boson production are in general
suppressed rendering conventional Higgs searches insensitive. However,
Drell-Yan Higgs pair production, which is not present in the SM, can be
sizeable even in the limit of vanishing exotic Higgs vacuum expectation value.
We utilize this to show that diphoton searches at 8 TeV LHC already rule out a
large class of neutral fermiophobic Higgs bosons below around 110 GeV. This
includes fermiophobic scalars found in two Higgs doublet as well as Higgs
triplet and Georgi-Machacek type models. Our results extend the only relevant
limit on fermiophobic Higgs bosons obtained by a recent CDF analysis of
$4\gamma + X$ Tevatron data. Furthermore, diphoton limits are independent of
the decay of the second Higgs boson and thus apply even for degenerate masses
in contrast to the CDF search. We also find that if the fermiophobic Higgs has
very enhanced couplings to photons, masses as large as $\sim 150$ GeV can be
ruled out while if these couplings are somehow highly suppressed, masses below
$\sim 90$ GeV can still be ruled out. Finally, we show that $WW$ and $ZZ$
diboson searches may serve as complementary probes for masses above the
diphoton limit up to $\sim 250$ GeV and discuss prospects at 13 TeV LHC.

High Energy Physics - Phenomenology;High Energy Physics - Experiment