Because of the problems arising from the fermion unification in the traditional Grand Unified Theory and the mass hierarchy between the 4-dimensional Planck scale and weak scale, we suggest the low energy gauge unification theory with low high-dimensional Planck scale. We discuss the non-supersymmetric SU(5) model on M × S/Z2 × S/Z2 and the supersymmetric SU(5) model on M × S/(Z2 × Z ′ 2) × S/(...

Models of supersymmetric grand unified theories based on the SU(5)GUT×U(N)H gauge group (N = 2, 3) have a symmetry that guarantees light Higgs doublets and the absence of dimension-five proton-decay operators. We analysed the proton decay induced by the gauge-boson exchange in these models. Upper bounds of proton lifetime are obtained; τ(p → πe)∼ 6.0 × 1033 yrs in the SU(5)GUT×U(2)H model and τ...

We present a grand unified theory (GUT) that has GUT fields with masses of the order of a TeV, but at the same time preserves (at the one-loop level) the success of gauge-coupling unification of the minimal supersymmetric standard model (MSSM) and the smallness of proton decay operators. This scenario is based on a five-dimensional theory with the extra dimension compactified as in the Randall-...

We present an extension of the Standard Model (SM) without supersymmetry, which we use to calculate order of magnitude values for the elements of the mass matrices in the SM. In our model we can fit the 9 quark and lepton masses and 3 mixing angles using only 3 free parameters, with the overall mass scale set by the electroweak interaction. The specific model described here has the anti-grand u...

Models of supersymmetric grand unified theories based on SU(5)GUT×U(N)H gauge group (N = 2, 3) have a symmetry that guarantees light two Higgs doublets and absence of dimension-five proton decay operators. We analysed the proton decay induced by gauge-boson exchange in the models. Upper bounds of proton life-time are obtained; τ(p → πe)∼ 6.0×1033 yrs. in the SU(5)GUT×U(2)H model and τ(p → πe)∼ ...

Based on a few basic assumptions, a predictive supersymmetric grand unification G U = SO(10) × ∆ 48 (SU (3)) × U (1) model is proposed. Thus, all the observed 45 chiral fermions with additional 3 right-handed neutrinos are unified into an irreducible triplet 16-dimensional spinor representation of G U. Electroweak symmetry breaking naturally requires two Higgs doublets which belong to a single ...

We suggest a simple grand unified theory where the fifth dimensional coordinate is compactified on an S/(Z2 × Z ′ 2) orbifold. This model contains additional 10 + 10, (15 + 15) and two 24 Higgs multiplets in the non-supersymmetric SU(5) grand unified theory. Although this model is non-supersymmetric theory, the gauge coupling unification is realized due to the mass splittings of Higgs multiplet...

It was recently suggested that the reported anomalies in Rb and Rc can be interpreted as the effect of a heavy vector boson that couples to quarks and is universally decoupled from leptons. We examine how an extra gauge boson with this property can arise from superstring derived models. In a specific three generation model we show that the U(1)B−L symmetry combines with the horizontal flavor sy...

In this paper we present a unified (probabilistic/possibilistic) model for resource-constrained project scheduling problem (RCPSP) with uncertain activity durations and a concept of a heuristic approach connected to the theoretical model. It is shown that the uncertainty management can be built into any heuristic algorithm developed to solve RCPSP with deterministic activity durations. The esse...