New Method for Detecting Charged (Pseudo-)Scalars at Colliders

Abstract

We propose a new method for detecting a charged (pseudo-)scalar at colliders, based upon the observation that its Yukawa coupling to charm and bottom quarks can be large due to a significant mixing of the top and charm quarks. After analyzing the typical flavor mixing allowed by low energy data in the topcolor and the generic two-Higgs doublet models, we study the physics potential of the Tevatron, LHC, and linear colliders for probing such an s-channel charged resonance via the single-top (as well as Wh^0) production. We show that studying its detection at colliders can also provide information on the dynamics of flavor-changing neutral current phenomena.

Figures (3)

• Figure 1: The $s$-channel $\phi^\pm$-production with the benchmark parameter choice of TopC models. As a reference, dashed curves show the results at Tevatron (2 TeV), LHC and $\gamma\gamma$ LCs, with top-pion Yukawa couplings satisfying the roughly estimated $3\sigma$$R_b$-bound Rb (reanalyzed with new $R_b^{\rm exp}$ data).
• Figure 2: $tb$ invariant-mass distribution of charged top-pion production, with its Yukawa coupling constrained by the estimated $3\sigma$$R_b$-bound. The (solid, dashed, dotted) curves are plotted for ${\cal C}_R^{cb}={\cal C}_R^{tb}\times (0.33,0.2,0.11)$, corresponding to 3 typical values of $t_R$-$c_R$ mixing parameter $K_{UR}^{tc}$ in eq. (6).
• Figure 3: Total decay widths (a) and branching ratios (b) of $\pi_t^\pm$ in the TopC model (solid), and of $H^\pm$ in the 2HDM (dashed) for the typical parameter choice in the text.