Multi-Lepton Signals of Multiple Higgs Bosons
  We identify and investigate novel multi-lepton signatures of extended Higgs sectors at the LHC in the guise of CP- and flavor-conserving two-Higgs-doublet models (2HDMs). Rather than designing individual searches tailored to specific 2HDM signals, we employ the combination of many exclusive multi-lepton search channels to probe the collective signal from the totality of production and decay processes. Multi-lepton signals of 2HDMs can arise from a variety of sources, including Standard Model-like production of the CP-even scalars, $h$ and $H$, through gluon-fusion with $h,H \to ZZ^{(*)}$, or associated production with vector bosons or top quarks, with $h,H \to WW^{(*)}, ZZ^{(*)},\tau\tau$. Additional sources include gluon-fusion production of the heavy CP-even scalar with decays through the light CP-even scalar, the CP-odd scalar, $A$, or the charged scalar, $H^\pm$, such as $H \to hh$, $H \to AA$, $H \to H^+ H^-$, $H \to ZA$, with $A \to Zh, \tau\tau$, $H^\pm \to Wh$, and $h \to WW^*, ZZ^*,\tau\tau$. Altogether, the combined multi-lepton signal may greatly exceed that of the Standard Model Higgs boson and provides a sensitive probe of extended Higgs sectors. As a proof of principle, we use a factorized mapping procedure between model parameters and signatures to determine multi-lepton sensitivities in four different flavor conserving 2HDM parameter spaces by simulating the acceptance times efficiency in 20 exclusive multi-lepton channels for 222 independent production and decay topologies that arise for four benchmark 2HDM spectra within each parameter space. A comparison of these sensitivities with the results of a multi-lepton search conducted by the CMS collaboration using 5 fb$^{-1}$ of data collected from 7 TeV $pp$ collisions yields new limits in regions of 2HDM parameter space that have not previously been covered by other types of direct experimental searches. 
Nathaniel Craig, Jared A. Evans, Richard Gray, Can Kilic, Michael   Park, Sunil Somalwar, Scott Thomas
hep-ph hep-ex