The NMSSM with and a moderate stop mass

Abstract

We study the generic NMSSM with the coupling λSH 1 H 2 at the limit of perturbativity, λ ≈ 0.7 ÷ 0.8, and a moderate stop mass, mt 300 GeV. Respecting the LEP2 bounds and insisting on naturalness, we delimit the allowed region of parameter space and we study the spectrum and phenomenology of the relatively light new particles.

The Next-to-Minimal Supersymmetric Standard Model

“…In the NMSSM this excess could be explained by • a SM-like CP-even scalar of corresponding mass and ξ ∼ 1, but with reduced BR(H → bb) ∼ 0.1 [70,202,205] due to a dominant decay H → A A with a branching ratio ∼0.8. This scenario could alleviate the little fine tuning problem related to the non-observation of a CP-even scalar at LEP (see Section 7.4), but requires M A < 10.5 GeV due to the constraints (2) on H → Φ Φ and Φ → bb; • a CP-even scalar H 1 of corresponding mass with ξ 0.4 [215] as it can appear, e.g., in the constrained NMSSM (see Section 7.1) [216,217] or for large λ ≈ 0.7 − 0.8 [218]. Then, another CP-even scalar H 2 with ξ 0.9 and a mass not far above 115 GeV is present in the spectrum.…”