Abstract
We revisit minimal supersymmetric SU(5) grand unification (GUT) models in which the soft supersymmetry-breaking parameters of the minimal supersymmetric Standard Model (MSSM) are universal at some input scale, $M_{in}$, above the supersymmetric gauge coupling unification scale, $M_{GUT}$. As in the constrained MSSM (CMSSM), we assume that the scalar masses and gaugino masses have common values, $m_0$ and $m_{1/2}$ respectively, at $M_{in}$, as do the trilinear soft supersymmetry-breaking parameters $A_0$. Going beyond previous studies of such a super-GUT CMSSM scenario, we explore the constraints imposed by the lower limit on the proton lifetime and the LHC measurement of the Higgs mass, $m_h$. We find regions of $m_0$, $m_{1/2}$, $A_0$ and the parameters of the SU(5) superpotential that are compatible with these and other phenomenological constraints such as the density of cold dark matter, which we assume to be provided by the lightest neutralino. Typically, these allowed regions appear for $m_0$ and $m_{1/2}$ in the multi-TeV region, for suitable values of the unknown SU(5) GUT-scale phases and superpotential couplings, and with the ratio of supersymmetric Higgs vacuum expectation values $\tan \beta \lesssim 6$.
Highlights
IntroductionIn our current state of confusion about the possible mechanism of supersymmetry breaking, and in the absence of a convincing dynamical origin at MGUT, one could well imagine that the universality scale Min might lie closer to the Planck or string scale: Min > MGUT
Fewer studies have been performed for scenarios in which the soft supersymmetry-breaking parameters are universal at some other scale Min = MGUT, which might be either below the grand unification (GUT) scale or above the GUT scale
To see the current and future limits on the constrained MSSM (CMSSM) parameter space from the LHC and future hadron colliders such as the 33 TeV HE-LHC option and the future circular collider (FCC) [153] which aims at 100 TeV proton–proton collisions, we show the limits from LHC at 8 TeV, and sensitivities with 300 and 3000 fb−1 with the LHC at 14 TeV, 3000 fb−1 with the HE-LHC at 33 TeV, and 3000 fb−1 with the FCC-hh at 100 TeV as the bold solid black, blue, green, purple, and red lines in each panel in Fig. 3, respectively, following the analysis given in Ref. [62]
Summary
In our current state of confusion about the possible mechanism of supersymmetry breaking, and in the absence of a convincing dynamical origin at MGUT, one could well imagine that the universality scale Min might lie closer to the Planck or string scale: Min > MGUT When studying such super-GUT scenarios, there appear additional ambiguities beyond those in the conventional CMSSM. It is well known that the length of the proton lifetime is a significant challenge for this model [88,89], and one of the principal new ingredients in this paper, compared to previous studies of super-GUT CMSSM models, is the incorporation of this constraint in our exploration of the model parameter space.
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