An Unusual Two Higgs Doublet Model from Warped Space

Abstract

We study a simple two Higgs doublet model (2HDM) in the Randall-Sundrum scenario, with an IR brane localized Higgs field and a second doublet arising from a $t\bar{t}$ condensate due to strong Kaluza-Klein gluon effects. The effective 2HDM predicts that the ratio of the brane to condensate vacuum expectation values $\tan \beta \sim 3$. It also predicts a standard model like Higgs boson of mass ${\mathcal{O}}(100)$ GeV and a heavier scalar at the scale of the lowest KK gluon mass, which we take to be $M_{KK} \gtrsim 1.5$ TeV. The pseudoscalar and the charged scalars are degenerate in mass at tree-level and are ${\mathcal{O}}(M_{KK})$. There are no tree-level flavor changing neutral currents (FCNC) for the down-type quarks and the standard model results hold there. In contrast, FCNC decays of the t-quark larger than in the SM are expected.