An Interesting NMSSM Scenario at the LHC and LC

Abstract

The Next-to-Minimal Supersymmetric Standard Model NMSSM provides an attractive extension to the minimal supersymmetric model by including an extra Higgs singlet superfield. This extension allows one to link the Higgs-higgsino mass parameter to a vacuum expectation value of the new scalar field, thus providing a solution to the mu-problem of the MSSM. It this report, presented within the context of the LHC / LC Study Group, we examine a particularly interesting NMSSM scenario where the extra Higgs scalar is rather light. We determine LHC production cross-sections and branching ratios for the lightest scalar and find that it will be difficult to observe at the LHC. However, we show that this lightest scalar can instead be observed at an electron-positron Linear Collider for all but a small window of parameter space.

Figures (5)

• Figure 1: The one-loop Higgs mass spectrum as a function of $M_A$ for $\lambda=0.3$, $\kappa=0.1$, $\tan \beta= \tan \beta_s =3$ and $A_{\kappa}=-60$ GeV. Also shown by the shaded area are the values of $M_A$ that are ruled out by LEP2 Barate:2003sz for this parameter choice.
• Figure 2: The dominant branching ratios for the lightest scalar Higgs boson as a function of $M_A$ for $\lambda=0.3$, $\kappa=0.1$, $\tan \beta= \tan \beta_s =3$ and $A_{\kappa}=-60$ GeV. The complicated structure is due to the switching off of the Higgs boson couplings to up-type and down-type quarks and leptons.
• Figure 3: Production cross-sections for the lightest scalar Higgs boson at the LHC, as a function of $M_A$ for $\lambda=0.3$, $\kappa=0.1$, $\tan \beta= \tan \beta_s =3$ and $A_{\kappa}=-60$ GeV.
• Figure 4: Production cross-sections for the lightest scalar Higgs boson at a $\sqrt{s}=500$ GeV LC, as a function of $M_A$ for $\lambda=0.3$, $\kappa=0.1$, $\tan \beta= \tan \beta_s =3$ and $A_{\kappa}=-60$ GeV. The cross-section for $e^+e^- \to H_1 b \bar{b}$ has been multiplied by $10^4$.
• Figure 5: Production cross-sections for the lightest scalar Higgs boson at a $\sqrt{s}=800$ GeV LC, as a function of $M_A$ for $\lambda=0.3$, $\kappa=0.1$, $\tan \beta= \tan \beta_s =3$ and $A_{\kappa}=-60$ GeV. The cross-section for $e^+e^- \to H_1 b \bar{b}$ has been multiplied by $100$.