Early Higgs Hints for Non-Minimal Supersymmetry

TL;DR

This paper investigates how Higgs coupling measurements constrain supersymmetric extensions of the Standard Model. By performing a model‑independent fit of Higgs couplings within a Type‑II 2HDM, the authors show that current data favor a SM‑like decoupling limit but also hint at suppressed down‑type Yukawas, which is difficult to reconcile with the MSSM for $\tan \beta>1$ due to its tree‑level quartic potential. They derive a general condition on the Higgs quartics for down‑suppression and discuss how MSSM loop corrections struggle to realize this while new dynamics (e.g., NMSSM singlets/triplets or extra doublets) can reopen the bottom‑suppressed region. The work provides a framework for interpreting future Higgs measurements in terms of extended Higgs sectors and places concrete targets on parameter space and scalar masses for experimental tests.

Abstract

We discuss the role that Higgs coupling measurements can play in differentiating supersymmetric extensions of the Standard Model. Fitting current LHC data to the Higgs couplings, we find that the likelihood fit shows a preference in the direction of suppressed (enhanced) bottom (top) quark couplings. In the minimal supersymmetric Standard Model, we demonstrate that for tan beta > 1, there is tension in achieving such fermion couplings due to the structure of the Higgs quartic couplings. In anticipation of interpreting supersymmetric models with future data, we determine a single straightforward condition required to access the region of coupling space preferred by current data.

Figures (3)

• Figure 1: The two regions accessible in a generic type-II 2HDM. Down-type couplings are enhanced when up-type are suppressed and vice versa. For the MSSM and simple extensions, the lower region is largely inaccessible when $\tan \beta > 1$.
• Figure 2: Likelihoods drawn from Higgs searches at ATLAS and CMS assuming that new loop-induced decays to SM states are small. The likelihood peaks below the decoupling contour, where down-type Yukawa couplings are suppressed.
• Figure 3: Likelihoods constructed in the three-dimensional space of gauge and Yukawa couplings of the Higgs, marginalizing over the gauge coupling in the range $0 \leq a \leq 1$. The colored contours show the space preferred by LHC data and the dashed red lines show how the fit is affected by the inclusion of Tevatron data. The two unshaded regions are those accessible in a type-II 2HDM; for $\tan \beta>1$, the MSSM is typically constrained to the up-suppressed region (cf. Fig \ref{['fig:TB']}).