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...

Equivalence in physics is discussed on the basis of experimental data accompanied by experimental errors. The introduction of the equivalence being consistent with the mathematical definition is possible only in theories constructed on nonstandard number spaces by taking the experimental errors as infinitesimal numbers of the non-standard spaces. Following the idea for the equivalence (the phys...

Recent developments in understanding non-harmonic gauge coupling constants in supersymmetry and superstring theory are summarized. Talk presented at the 2nd International Symposium on Particles, Strings and Cosmology, Boston, MA, March 25-30,199l * Work supported by the Department of Energy, contract DE-AC03-76SF00515.

The measurement and QCD analysis of neutral and charged current cross sections at HERA are presented. For the kinematic range of four-momentum transfer Q 2 between ≈ 1 GeV 2 and 30000 GeV 2 and Bjorken x between 0.0013 and 0.65 the data are compared to NLO QCD predictions. In dedicated NLO QCD analyses the extraction of the parton distribution functions of the proton is performed. Results for t...

We provide an introduction to recent lattice formulations of supersymmetric theories which are invariant under one or more real supersymmetries at nonzero lattice spacing. These include the especially interesting case of N = 4 SYM in four dimensions. We discuss approaches based both on twisted supersymmetry and orbifold-deconstruction techniques and show their equivalence in the case of gauge t...

The Symanzik action improvement program has been proposed [1,2] as a way to reduce scaling violations in the approach to the continuum limit from a lattice action. In another contribution, we report on our preliminary investigations into the nature of scaling violations inherent in improved actions. In another proceedings in this volume[4], we make detailed comparisons of Wilson and tadpole-imp...

The measurement and QCD analysis of neutral and charged current cross sections at HERA are presented. For the kinematic range of four-momentum transfer Q 2 between ≈ 1 GeV 2 and 30000 GeV 2 and Bjorken x between 0.0013 and 0.65 the data are compared to NLO QCD predictions. In dedicated NLO QCD analyses the extraction of the parton distribution functions of the proton is performed. Results for t...

We present preliminary results for the ∆I = 3/2 kaon decay matrix elements using domain wall fermions and the DBW2 gauge action at one coarse lattice spacing corresponding to a−1 = 1.3 GeV. We employ an extention of the Lellouch and Lüscher formula for non-zero total momentum to extract the infinite volume, center-of-mass system decay amplitudes. We compare the result of ReA2 with previous resu...

We consider the evolution of the phase transition from the parent hexagonal phase P63/mmc to the orthorhombic phase Pmcn that occurs in several compounds of A′A′′BX4 family as a function of the hcp lattice parameter c/a. For compounds of K2SO4 type with c/a larger than the threshold value 1.26 the direct first-order transition Pmcn−P63/mmc is characterized by the large entropy jump ∼ R ln 2. Fo...