Does LEP prefer the NMSSM?

Abstract

We study the naturalness of electroweak symmetry breaking and baryogenesis in the next-to-minimal supersymmetric standard model (NMSSM). Our study is motivated by the recent LEP bounds on the Higgs boson mass which severely constrains the low \tan\beta region of the minimal supersymmetric standard model (MSSM). We show that the low \tan \beta region of the NMSSM is clearly favoured over the MSSM with regard to the physical Higgs boson mass, fine-tuning, and electroweak baryogenesis.Comment: 17 pages, Latex, 3 eps figures, typos corrected, reference adde

Enhanced diphoton rates at Fermi and the LHC

“…As in the NMSSM there is an additional tree-level contribution to the lightest Higgs mass, which is large for small tan β and large λ, allowing to evade the upper bound of m h < M Z present in the MSSM. The fact that radiative corrections due to top/stop loops are no longer needed drastically reduces the electroweak fine-tuning in MSSM singlet extensions [58][59][60][61][62] for large values of λ. Given the Higgs mass of 125 GeV the GNMSSM has been shown to be particularly interesting in this context [52,55].…”

NSUSY fits

“…This can happen through new sectors coupled to the Higgs in such a way that they add at tree-level new supersymmetric F -term or D term (or even susy-breaking) contributions to the Higgs quartic even in the Higgs decoupling limit (see [111][112][113][114][115][116][117][118][119][120][121][122][123][124][125][126] for an incomplete list of studies on this). A very moderate tree-level upward shift of this quartic, which can be interpreted as a threshold correction at the SUSY scale, would have a direct and very important impact on increasing the predicted Higgs mass and reducing the associated finetuning.…”

Collider signatures of singlet extended Higgs sectors

“…2a, due to larger Yukawa couplings. Production modes via vector boson fusion are subdominant but 2 The scan of the n/sMSSM is slightly different from Ref. [10] in that a uniformly random scan over the parameters t S and t F is performed here whereas the scan of Ref.…”

“…The models we focus on include the Next-to-Minimal Supersymmetric SM (NMSSM) [2], the Nearly-Minimal Supersymmetric SM (nMSSM) [3,4,5], and the U(1) ′ -extended MSSM (UMSSM) [6], as detailed in Table I with the respective symmetries 1 . A Secluded U(1) ′ -extended MSSM (sMSSM) [8,9] contains three singlets in addition to the standard UMSSM Higgs singlet; this model is equivalent to the nMSSM in the limit that the additional singlet vevs are large, and the trilinear singlet coupling, λ s , is small [10].…”