Off-diagonal terms in Yukawa textures of the Type-III 2-Higgs doublet model and light charged Higgs boson phenomenology

Abstract

We discuss flavor-violating constraints and consequently possible charged Higgs boson phenomenology emerging from a four-zero Yukawa texture embedded within the Type-III 2-Higgs Doublet Model (2HDM-III). Firstly, we show in detail how we can obtain several kinds of 2HDMs when some parameters in the Yukawa texture are absent. Secondly, we present a comprehensive study of the main B-physics constraints on such parameters induced by flavor-changing processes, in particular on the off-diagonal terms of such a texture: i.e., from $\mu -e$ universality in $\tau$ decays, several leptonic B-decays ($B\to \tau \nu$, $D\to \mu \nu$ and $D_s\to l\nu$), the semi-leptonic transition $B\to D\tau \nu$, plus $B\to X_s\gamma$, including $B^0-{\bar{B}}^0$ mixing, $B_s\to {\mu }^{+}{\mu }^{-}$ and the radiative decay $Z\to b\bar{b}$. Thirdly, having selected the surviving 2HDM-III parameter space, we show that the $H^{-}c\bar{b}$ coupling can be very large over sizable expanses of it, in fact, a very different situation with respect to 2HDMs with a flavor discrete symmetry (i.e., ${\mathcal{Z}}_2$) and very similar to the case of the Aligned-2HDM (A2HDM) as well as of models with three or more Higgs doublets. Fourthly, we study in detail the ensuing $H^{\pm }$ phenomenology at the Large Hadron Collider (LHC), chiefly the $c\bar{b}\to H^{+}$ production mode and the $H^{+}\to c\bar{b}$ decay channel while assuming ${\tau }^{+}{\nu }_{\tau }$ decays in the former and $t\to b{H}^{+}$ production in the latter, showing that significant scope exists in both cases.

Comments: 50 pages, 22 figures; version accepted by JHEP. arXiv admin note: text overlap with arXiv:1203.5769; and text overlap with arXiv:0906.5139, arXiv:1006.0470, arXiv:hep-ph/0309103 by other authors. text overlap with arXiv:1006.0470, arXiv:0906.5139 by other authors