Multi-tau-lepton signatures at the LHC in the two Higgs doublet model
  A detailed simulation study is performed for multi-tau-lepton signatures at the Large Hadron Collider, which can be used to probe additional Higgs bosons with lepton-specific Yukawa interactions. Such an extended Higgs sector is introduced in some of new physics models at the TeV scale. We here consider the two Higgs doublet model with the Type-X Yukawa interaction, where nonstandard Higgs bosons predominantly decay into tau leptons. These extra Higgs bosons can be pair produced via s-channel gauge boson mediation at hadron colliders; q \bar q \to Z \to HA and q \bar q' \to W^\pm \to HH^\pm (AH^\pm), where H, A and H^\pm are CP-even, odd and charged Higgs bosons, respectively. Consequently, multi-tau-lepton originated signals appear in the final state as a promising signature of such a model. We find that the main background can be considerably reduced by requiring the high multiplicity of leptons and tau-jets with appropriate kinematical cuts in the final state. Thus, assuming the integrated luminosity of a hundred of inverse fb, the excess can be seen in various three- and four-lepton channels. With the integrated luminosity of thousands of inverse fb, the determination of the mass as well as ratios of leptonic decay branching ratios of these Higgs bosons would also be possible. 
Shinya Kanemura, Koji Tsumura, Hiroshi Yokoya
hep-ph