Escaping the Large Fine Tuning and Little Hierarchy Problems in the Next to Minimal Supersymmetric Model and h-> aa Decays

TL;DR

It is demonstrated that the next to minimal supersymmetric model can have small fine-tuning and modest top-squark mass while still evading all experimental constraints.

Abstract

We demonstrate that the NMSSM can have small fine tuning and modest light stop mass while still evading all experimental constraints. For small tan(beta) [large tan(beta)], the relevant scenarios are such that there is always (often) a SM-like Higgs boson that decays to two lighter -- possibly much lighter -- pseudoscalar Higgses.

Figures (4)

• Figure 1: Left: the fine-tuning measure $F$ in the MSSM is plotted vs. $\sqrt{m_{\widetilde{t}_1} m_{\widetilde{t}_2}}$, without regard to LEP constraints on $m_{h}$. The $+$ points have $m_{h}<114~{\rm GeV}$ and are excluded by LEP limits. The $\times$ points have $m_{h}>114~{\rm GeV}$ and are experimentally allowed. Right: $F$ is plotted vs. $m_{h}$ for all scanned points.
• Figure 2: For the NMSSM, we plot the fine-tuning measure $F$ vs. $\sqrt{m_{\widetilde{t}_1} m_{\widetilde{t}_2}}$ for NMHDECAY-accepted scenarios with $\tan\beta=10$ and $M_{1,2,3}(m_Z)=100,200,300~{\rm GeV}$. Points marked by '$+$' ('$\times$') escape LEP exclusion primarily due to dominance of $h_1\to a_1a_1$ decays (due to $m_{h_1}>114~{\rm GeV}$).
• Figure 3: For the NMSSM, we plot the fine-tuning measure $F$ vs. $m_{h_1}$ for NMHDECAY-accepted scenarios with $\tan\beta=10$ and $M_{1,2,3}(m_Z)=100,200,300~{\rm GeV}$. Point labeling as in Fig. \ref{['nmssm']}.
• Figure 4: For the NMSSM, we plot the fine-tuning measure $F$ vs. $\sqrt{m_{\widetilde{t}_1} m_{\widetilde{t}_2}}$ for NMHDECAY-accepted scenarios with $\tan\beta=3$ and $M_{1,2,3}(m_Z)=100,200,300~{\rm GeV}$. Point labeling as in Fig. \ref{['nmssm']}.