In this talk a search for the single production of top quarks performed at the H1 experiment is presented. No evidence for anomalous top production via FCNC processes is found and limits on the anomalous magnetic coupling constant κtuγ are given.

There is a convincing experimental evidence that neutrinos are massive. Therefore we investigate the influence of the neutrino masses on the unification of gauge and Yukawa couplings in the framework of the Minimal Supersymmetric Standard Model. We estimate the contribution of the neutrino Yukawa coupling to the gauge and Yukawa coupling unification. We find that in the case of the gauge coupli...

The fermion and meson sectors of the quark-level SU(2) linear sigma model are dynamically generated from a meson-quark Lagrangian, with the quark (q) and meson (σ, π) fields all treated as elementary, having neither bare masses nor expectation values. In the chiral limit, the masses are predicted to be mq = fπg, mπ = 0, mσ = 2mq, and we also find that the quark-meson coupling is g = 2π/ √ Nc, t...

By (a) using an expression for the lattice potential of QCD in terms of a continuum running coupling and (b) globally parameterizing this coupling to interpolate between 2(or higher-) loop QCD in the UV and the flux tube prediction in the IR, we can perfectly fit lattice data for the potential down to one lattice spacing and at the same time extract the running coupling to high precision. This ...

We consider the ground state properties of an inhomogeneous twodimensional Bose gas with a repulsive, short range pair interaction and an external confining potential. In the limit when the particle number N is large but ρ̄a2 is small, where ρ̄ is the average particle density and a the scattering length, the ground state energy and density are rigorously shown to be given to leading order by a Gr...

We study the properties of heavy fermions in the vector-like representation of the electro-weak gauge group SU(2)W × U(1)Y with Yukawa couplings to the standard model Higgs boson. Using the renormalization group analysis, we discuss their effects on the vacuum stability and the triviality bound on the Higgs self-coupling, within the context of the standard model (i.e., the Higgs particle is ele...

We consider the wide class of few-particle systems that have some analog of the thermodynamic laws. These systems are characterized by the distributions that are determined by the Hamiltonian and satisfy the Liouville equation. Few-particle systems of this class are described by a non-holonomic constraint: the power of non-potential forces is directly proportional to the velocity of the element...