Abstract
We propose a simple grand unified theory (GUT) scenario in which supersymmetry (SUSY) is spontaneously broken in visible sector. Our model is based on the GUT model that has been proposed to solve almost all problems in conventional GUT scenarios. In the previous work, the problems can be solved by a natural assumption in a supersymmetric vacuum. In this paper, we consider an extension of the model (i.e. omitting one singlet field) and break SUSY spontaneously without new sector. Our model does not have hidden sector and predicts high-scale SUSY where sfermion masses are of order 100-1000 TeV and flavor violating processes are suppressed. In this scenario, we can see an explicit signature of GUT in sfermion mass spectrum since the sfermion mass spectrum respects SU(5) matter unification. In addition, we find a superheavy long lived charged lepton as a proof of our scenario, and it may be seen in the LHC.
Highlights
Grand unified theory (GUT) [1] realizes two kinds of unification
We have proposed a simple grand unified theory (GUT) scenario in which SUSY is spontaneously broken in the visible sector
We have started with the natural GUT, in which almost all problems including the doublet-triplet splitting problem can be solved under the natural assumption that all interactions allowed by the symmetry are introduced with O(1) coefficients
Summary
Grand unified theory (GUT) [1] realizes two kinds of unification. Three gauge groups SUð3ÞC × SUð2ÞL × Uð1ÞY in the standard model (SM) can be unified into a single group SUð5Þ, SOð10Þ, or E6, which leads to the unification of forces. In SOð10Þ GUT, these fields as well as the right-handed neutrino are unified into a single multiplet 16, which results in the unification of matters. A fine-tuning is needed to obtain the weak scale mass of the SM Higgs (doublet Higgs) and the colored Higgs (triplet Higgs) mass larger than the GUT scale because the doublet Higgs and triplet Higgs are included in the same multiplet 5 of SUð5Þ Another problem is that the matter unification results in unrealistic Yukawa relations in simple GUT models. In the minimal SOð10Þ GUT, all the Yukawa matrices become equal as Yu 1⁄4 Yd 1⁄4 Ye 1⁄4 YνD , where Yu and YνD are Yukawa matrices of the up quark and the Dirac neutrino These Yukawa relations are inconsistent with the observed quark and lepton masses, so some improvements are needed to obtain realistic Yukawa couplings.
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