Heavy Higgs bosons at the LHC upgrade

We evaluate the discovery potential for the heavy Higgs bosons at the LHC energy upgrade with s√=27 TeV.We assume the degenerate mass spectrum and an approximate alignment limit in the Type-II Two Higgs Doublet Model for illustration.We explore the observability of the heavy neutral Higgs bosons by examining the clean signals from H^0→W+W−,ZZ via gluon-gluon fusion production.The associated production of a top quark and a charged Higgs boson via gb→tH^±is adopted to predict the discovery potential of heavy charged Higgses.We also emphasize the potential importance of the electroweak production of Higgs boson pairs,i.e.pp→W^∗→H^±A0 and pp→Z^∗/γ^∗→H^+H^-.These are only governed by pure electroweak gauge couplings and can provide complementary information to the conventional signals in the determination of the nature of the Higgs sector.