Constraining Type II 2HDM in Light of LHC Higgs Searches

Abstract

We study the implication of the LHC Higgs search results on the Type II Two Higgs-Doublet Model. In particular, we explore the scenarios in which the observed 126 GeV Higgs signal is interpreted as either the light CP-even Higgs $h^0$ or the heavy CP-even Higgs $H^0$. Imposing both theoretical and experimental constraints, we analyze the surviving parameter regions in $m_H$ ($m_h$), $m_A$, $m_{H^{\pm }}$, $\tan {\hat{I}}^2$ and $\sin ({\hat{I}}^2-\hat{I}\pm )$. We further identify the regions that could accommodate a 126 GeV Higgs with cross sections consistent with the observed Higgs signal. We find that in the $h^0$-126 case, we are restricted to narrow regions of $\sin ({\hat{I}}^2-\hat{I}\pm )\approx \pm 1$ with $\tan {\hat{I}}^2$ up to 4, or an extended region with $0.55<\sin ({\hat{I}}^2-\hat{I}\pm )<0.9$ and $1.5<\tan {\hat{I}}^2<4$. The values of $m_H$, $m_A$ and $m_{H^{\pm }}$, however, are relatively unconstrained. In the $H^0$-126 case, we are restricted to a narrow region of $\sin ({\hat{I}}^2-\hat{I}\pm )\sim 0$ with $\tan {\hat{I}}^2$ up to about 8, or an extended region of $\sin ({\hat{I}}^2-\hat{I}\pm )$ between $-0.8$ to $-0.05$, with $\tan {\hat{I}}^2$ extended to 30 or higher. $m_A$ and $m_{H^{\pm }}$ are nearly degenerate due to $\hat{I}”\ddot{I}$ constraints. Imposing flavor constraints shrinks the surviving parameter space significantly for the $H^0$-126 case, limiting $\tan {\hat{I}}^2\lesssim 10$, but has little effect in the $h^0$-126 case. We also investigate the correlation between ${\hat{I}}^3{\hat{I}}^3$, $VV$ and $bb/\ddot{I}„\ddot{I}„$ channels. ${\hat{I}}^3{\hat{I}}^3$ and $VV$ channels are most likely to be highly correlated with ${\hat{I}}^3{\hat{I}}^3:VV\sim 1$ for the normalized cross sections.

34 pages, 18 figures