I argue that in open-string theory with hierarchically small (or large) extra dimensions, gauge groups can unify naturally with logarithmically-running coupling constants at the high Kaluza-Klein (or string-winding) scale. This opens up the possibility of rescuing the standard logarithmic unification atMU ∼ 1015−18 GeV even if the fundamental-string scale is much lower, at intermediate or possi...

The renormalization group is used to resum leading logarithmic contributions of the form αn+1 s β n 0 log n (∆/μ) to the gap equation appropriate for high density QCD. The scale dependence of the strong coupling constant αs increases the gap by a factor of exp (

By making use of the duality transformation, gauge field correlators of the Abelian Higgs Model are studied in the London limit. The obtained results are in a good agreement with the dual Meissner scenario of confinement and with the Stochastic Model of QCD vacuum. The nontrivial contribution to the quartic correlator arising due to accounting for the finiteness of the coupling constant is disc...

In scalar field theories the Landau pole is an ultraviolet singularity in the running coupling constant that indicates a mass scale at which the theory breaks down and new physics must intervene. However, new physics at the pole will in general affect the running of the low energy coupling constant, which will in turn affect the location of the pole and the related upper limit (“triviality” bou...

A study of the energy dependence of event shape observables is presented. The strong coupling constant αs has been determined from the mean values of six event shape observables. Power corrections, employed for the measurement of αs, have been found to approximately account for hadronisation effects.

Recent data on the D∗ masses confirm the QCD prediction based on the very general assumption [1] that the spin-dependence of the quark couplings to photons and gluons have the same structure and differ only in the value of the coupling constants, This prediction with no free parameters and using the Ξ and Ξ∗ masses as input follows from noting that the charmed antiquark c̄ and the strange diquar...

A coupled-oscillators-model-based method for measuring speech rhythm is presented. This model explains crosslinguistic differences in rhythm as deriving from varying degrees of coupling strength between a syllable oscillator and a phrase stress oscillator. The method was applied to three texts read aloud in French, in Brazilian and European Portuguese by seven speakers. The results reproduce th...

Recent progress in some selected areas of grand unification and physics beyond the standard model is reviewed. Topics include gauge coupling unification, SU(5), SO(10), symmetry breaking mechanisms, finite field theory: SU(3), leptonic color: SU(3), chiral color and quark-lepton nonuniversality: SU(3). **Talk at V-SILAFAE, Lima, Peru (July 2004).

Abstract We consider compactifications of the heterotic string on K3×T2 so that the resulting theory in d = 4 space-time dimensions has N = 2 supersymmetry. The gravitational and gauge coupling constants of the low-energy effective theory receive threshold corrections from loops of super-heavy string states. We calculate these corrections for the case when the K3-surface is a Zn orbifold of a f...

We have built an effective Walecka-type hadronic Lagrangian in which the hadron masses and the density dependence of the coupling constants are deduced from the quark dynamics using a Nambu-Jona-Lasinio model. The parameters of this Nambu-Jona-Lasinio model have been determined using the meson properties in the vacuum but also in the medium through the omega meson mass in nuclei measured by the...