We consider the Higgs boson signals from pair production at the LHC within
the framework of the MSSM in the non-decoupling (low-m_A) region. In light of
the recent observation of a SM-like Higgs boson, we argue that the exploration
for Higgs pair production at the LHC is a crucial next step to probe the MSSM
Higgs sector. We emphasize that the production of H^\pm A^0 and H^{+}H^{-}
depends only on the electroweak gauge couplings while all the leading Higgs
production channels via gluon fusion, vector-boson fusion, and Higgsstrahlung
depend on additional free Higgs sector parameters. In the non-decoupling
region, the five MSSM Higgs bosons are all relatively light and pair production
signals may be accessible. We find that at the 8 TeV LHC, a 5\sigma signal for
H^\pm A^0, H^\pm h^0 -> \tau^{\pm}\nu b\bar b and H^{+}H^{-} -> \tau^{+}\nu
\tau^{-}\nu are achievable with an integrated luminosity of 7 (11) fb^{-1} and
24 (48) fb^{-1}, respectively for m_A=95 (130) GeV. At the 14 TeV LHC, a
5\sigma signal for these two channels would require as little as 4 (7) fb^{-1}
and 10 (19) fb^{-1}, respectively.Comment: 20 pages, 8 figures and 3 tables. Version to appear in PR