Exotic Higgs Decays

Abstract

Many models of physics beyond the Standard Model include an extended Higgs sector, responsible for electroweak symmetry breaking, and predict the existence of additional Higgs bosons. The Type II Two-Higgs-Doublet Model (2HDM) is a particularly well motivated scenario and a suitable framework for phenomenological studies of extended Higgs sectors. Its low energy spectrum includes two CP-even Higgses h and H, one CP-odd Higgs A, and a pair of charged Higgses H±. We study the implication of the LHC Higgs search results on the Type II 2HDM and identify regions of parameter space which are consistent with all experimental and theoretical constraints and can accommodate the observed 125 GeV Higgs signal. This includes parameter space with a distinctive mass hierarchy which permit a sizable mass splitting between the undiscovered non-Standard Model Higgs states. If this mass splitting is large enough, exotic Higgs decay channels into either a Higgs plus a Standard Model gauge boson or two lighter Higgses open up. This can significantly weaken the reach of the conventional Higgs decay channels into Standard Model particles but also provide the additional opportunity to search for exotic Higgs decay channels. We provide benchmark planes to explore exotic Higgs decay scenarios and perform detailed collider analyses to study the exotic decay channels H/A -> AZ/HZ and H± -> AW/HW. We find that these exotic decays offer complementary discovery channels to the conventional modes for both neutral and charged Higgs searches and permit exclusion and discovery in large regions of parameter space.