Implications of a 125 GeV Higgs for supersymmetric models

Abstract

Preliminary results of the search for a Standard Model like Higgs boson at the LHC with 5 fb-1 data have just been presented by the ATLAS and CMS collaborations and an excess of events at a mass of ~125 GeV has been reported. If this excess of events is confirmed by further searches with more data, it will have extremely important consequences in the context of supersymmetric extensions of the Standard Model and, in particular the minimal one, the MSSM. We show that for a standard-like Higgs boson with a mass 123 < M_h < 127 GeV, several unconstrained or constrained (i.e. with soft supersymmetry-breaking parameters unified at the high scale) MSSM scenarios would be excluded, while the parameters of some other scenarios would be severely restricted. Examples of constrained MSSM scenarios which would be disfavoured as they predict a too light Higgs particle are the minimal anomaly and gauge mediated supersymmetry breaking models. The gravity mediated constrained MSSM would still be viable, provided the scalar top quarks are heavy and their trilinear coupling large. Significant areas of the parameter space of models with heavy supersymmetric particles, such as split or high-scale supersymmetry, could also be excluded as, in turn, they generally predict a too heavy Higgs particle.

Figures (5)

• Figure 1: The maximal value of the $h$ boson mass as a function of $X_t/M_S$ in the pMSSM when all other soft SUSY--breaking parameters and $\tan\beta$ are scanned in the range Eq. (\ref{['scan-range']}) (left) and the contours for 123$<M_h<$127 GeV in the $[M_S,X_t]$ plane for some selected range of $\tan\beta$ values (right).
• Figure 2: The maximal value of the $h$ mass defined as the value for which 99% of the scan points have a mass smaller than it, shown as a function of $\tan\beta$ for the various constrained MSSM models.
• Figure 3: The value of $M_h$ as a function of one mSUGRA continuous parameter when a scan is performed on the other parameters. The constraints from Higgs and SUSY searches at the LHC are included and the impact of flavour ($b\to s\gamma, B_s \to \mu^+ \mu^-$, $B\to \tau\nu$) and DM constraints are shown.
• Figure 4: Contours in which 123 $< M_h <$ 127 GeV, resulting of a full scan of the mSUGRA parameter but for particular choices of the inputs $A_0$ (left) and $m_0$ (right). The lower bound from LHC searches of SUSY strongly interacting particles in the fully hadronic channel with 1 fb$^{-1}$ data CMS-SUSY is shown by a continuous line.
• Figure 5: The value of $M_h$ as a function of $M_S$ for several values of $\tan\beta=1,2,5,50$ in the split SUSY (left) and high--scale SUSY (right) scenarios.