Probing NMSSM Scenarios with Minimal Fine-Tuning by Searching for Decays of the Upsilon to a Light CP-Odd Higgs Boson

Abstract

Completely natural electroweak symmetry breaking is easily achieved in supersymmetric models if there is a SM-like Higgs boson, $h$, with $m_h\lsim 100\gev$. In the minimal supersymmetric model, such an $h$ decays mainly to $b\anti b$ and is ruled out by LEP constraints. However, if the MSSM Higgs sector is expanded so that $h$ decays mainly to still lighter Higgs bosons, e.g. $h\to aa$, with $BR(h\to aa)>0.7$, and if $m_a<2m_b$, then the LEP constraints are satisfied. In this letter, we show that in the next-to-minimal supersymmetric model the above $h$ and $a$ properties (for the lightest CP-even and CP-odd Higgs bosons, respectively) imply a lower bound on $BR(Υ\to \gam a)$ that dedicated runs at present (and future) $B$ factories can explore.

Figures (2)

• Figure 1: ${\rm Br}(\Upsilon\to\gamma a_1)$ for NMSSM scenarios with various ranges for $m_{a_1}$: dark grey (blue) = $m_{a_1}<2m_\tau$; medium grey (red) = $2m_\tau<m_{a_1}<7.5~{\rm GeV}$; light grey (green) = $7.5~{\rm GeV}<m_{a_1}<8.8~{\rm GeV}$; and black = $8.8~{\rm GeV}<m_{a_1}<9.2~{\rm GeV}$. The plots are for $\tan\beta=10$ and $M_{1,2,3}(m_Z)=100,200,300~{\rm GeV}$. The left plot comes from the $A_\lambda,A_\kappa$ scan described in the text, holding $\mu_{\rm eff}(m_Z)=150~{\rm GeV}$ fixed. The right plot shows results for $F<15$ scenarios with $m_{a_1}<9.2~{\rm GeV}$ found in a general scan over all NMSSM parameters holding $\tan\beta$ and $M_{1,2,3}$ fixed as stated.
• Figure 2: We plot ${\rm Br}(\Upsilon\to \gamma a_1)$ as a function of $\cos\theta_A$ for the $A_\lambda,A_\kappa$ scan, taking $M_{1,2,3}(m_Z)=100,200,300~{\rm GeV}$, $\mu_{\rm eff}(m_Z)=150~{\rm GeV}$ with $\tan\beta=3$ (left) and $\tan\beta=50$ (right). The point notation is as in Fig. \ref{['upsilon']}.