Top quark, heavy fermions and the composite Higgs boson

We study the properties of heavy fermions in the vector-like representation of the electro-weak gauge group $SU(2)_W\times U(1)_Y$ with Yukawa couplings to the standard model Higgs boson. Applying the renormalization group analysis, we discuss the effects of heavy fermions to the vacuum stability bound and the triviality bound on the mass of the Higgs boson. We also discuss the interesting possibility that the Higgs particle is composed of the top quark and heavy fermions. The bound on the composite Higgs mass is estimated using the method of Bardeen, Hill and Lindner, 150GeV$\leq m_H\leq$ 450GeV.Comment: 10 pages and 6 figures. This paper replaces and is an extended version of hep-ph/9602340 (published in Phys. Lett. B370(1996)201;Erratum B382(1996)448

Some new generalized 2D Ostrowski-Grüss type inequalities on time scales

AbstractIn this paper, we present some new generalized 2D Ostrowski-Grüss type integral inequalities on time scales, which on one hand extend some known results in the literature, and on the other hand unify corresponding continuous and discrete analysis. New bounds for the 2D Ostrowski-Grüss type inequalities are derived, some of which are sharp

Computational approaches to the design and analysis of stability of polypeptide multilayer thin films

The focus of this research is the development of computational approaches to understanding the physical basis of layer-by-layer assembly (LBL), a key methodology of nanomanufacturing. The results provided detailed information on structure which cannot be obtained directly by experiments. The model systems chosen for study are polypeptide chains. Reasons for this are that polypeptides are no less polyelectrolytes than the more usual polyions, and one can control the primary structure of a polypeptide on a residue-by-residue basis using modern synthetic methods. Moreover, as peptides constitute one of the four major classes of biological macromolecules, research in this direction is expected to advance development of bionanotechnology. Polypeptide thin films are a type of new material, and there is great potential for applications in biocompatible implants, drug delivery, and other areas. A key consideration in polypeptide design for LBL is charge properties as a function of pH. This work presents a computational approach to identify structural motifs in amino acid sequence data and to minimize the immune response to polypeptides based on the structural motifs and demonstrate by experiments. This work also presents innovative molecular dynamics (MD) work on LBL. All-atom models have been used to investigate polypeptide LBL at the sub-molecular level. The peptide structures studied—homopolymers of lysine and of glutamic acid, and designed cysteine-containing peptides—correspond to ones for which experimental data have been obtained in the Haynie research laboratory. Simulations were carried out to study structural and dynamical properties of peptide models having some combination of parallel and anti-parallel β sheets, as such structures are known to be formed by the indicated peptides in LBL films. The MD work suggests that hydrophobic interactions too play an important role in polypeptide LBL. Moreover, hydrogen bonding appears to be a consequence of polypeptide LBL instead of a major driving force for stabilizing secondary structures in polypeptide multilayer thin films. Results of simulations of 6-residue and 8-residue peptides further suggest that if the shorter peptides can form a stable superstructure in the vicinity of 350 K, the most likely conformation will be anti-parallel β strands within a layer and parallel β strands between layers

Partial Synchronization on Complex Networks

Network topology plays an important role in governing the collective dynamics. Partial synchronization (PaS) on regular networks with a few non-local links is explored. Different PaS patterns out of the symmetry breaking are observed for different ways of non-local couplings. The criterion for the emergence of PaS is studied. The emergence of PaS is related to the loss of degeneration in Lyapunov exponent spectrum. Theoretical and numerical analysis indicate that non-local coupling may drastically change the dynamical feature of the network, emphasizing the important topological dependence of collective dynamics on complex networks.Comment: 4 pages, 4 figure