Top-BESS model and its phenomenology

We introduce the top-BESS model which is the effective description of the strong electroweak symmetry breaking with a single new SU(2)_L+R triplet vector resonance. The model is a modification of the BESS model in the fermion sector. The triplet couples to the third generation of quarks only. This approach reflects a possible extraordinary role of the top quark in the mechanism of electroweak symmetry breaking. The low-energy limits on the model parameters found provide hope for finding sizable signals in the LHC Drell-Yan processes as well as in the s-channel production processes at the ILC. However, there are regions of the model parameter space where the interplay of the direct and indirect fermion couplings can hide the resonance peak in a scattering process even though the resonance exists and couples directly to top and bottom quarks.Comment: published in Physical Review D, minor changes in text, 21 pages, 37 figure

Effect of fluoride toothpastes on enamel demineralization

BACKGROUND: It was the aim of this study to investigate the effect of four different toothpastes with differing fluoride compounds on enamel remineralization. METHODS: A 3 × 3 mm window on the enamel surface of 90 human premolars was demineralized in a hydroxyethylcellulose solution at pH 4.8. The teeth were divided into 6 groups and the lower half of the window was covered with varnish serving as control. The teeth were immersed in a toothpaste slurry containing: placebo tooth paste (group 1); remineralization solution (group 2); Elmex Anticaries (group 3); Elmex Sensitive (group 4); Blend-a-med Complete (group 5) and Colgate GRF (group 6). Ten teeth of each group were used for the determination of the F(- )content in the superficial enamel layer and acid solubility of enamel expressed in soluble phosphorus. Of 6 teeth of each group serial sections were cut and investigated with polarization light microscopy (PLM) and quantitative energy dispersive X-ray analysis (EDX). RESULTS: The PLM results showed an increased remineralization of the lesion body in the Elmex Anticaries, Elmex Sensitive and Colgate GRF group but not in the Blend-a-med group. A statistically significant higher Ca content was found in the Elmex Anticaries group. The fluoride content in the superficial enamel layer was significantly increased in both Elmex groups and the Blend-a-med group. Phosphorus solubility was significantly decreased in both Elmex groups and the Blend-a-med group. CONCLUSION: It can be concluded that amine fluoride compounds in toothpastes result in a clearly marked remineralization of caries like enamel lesions followed by sodium fluoride and sodium monofluorophosphate formulations

Top-quark couplings to TeV resonances at future lepton colliders

We study the processes $W_L W_L \to t \bar t$ and $W_L Z_L \to t\bar b (\bar t b)$ at future lepton colliders as probes of the couplings of the top quark to resonances at the TeV scale. We consider the cases in which the dominant low energy feature of a strongly interacting electroweak symmetry breaking sector is either a scalar or a vector resonance with mass near 1 TeV. We find that future lepton colliders with high energy and high luminosity have great potential to sensitively probe these physics scenarios. In particular, at a 1.5 TeV linear collider with an integrated luminosity of 200 fb$^{-1}$, we expect about 120 events for either a scalar or a vector to decay to $t\bar t, t \bar b$. Their leading partial decay widths, which characterize the coupling strengths, can be statistically determined to about 10% level.Comment: 33 pages, 9 ps figures, 1 tabl

Study of Anomalous Couplings at a 500500~GeV e+e−e^+e^- Linear Collider with Polarized Beams

We consider the possibility of observing deviations from the Standard Model gauge-boson self-couplings at a future $500$~GeV $e^+ e^-$ linear collider. We concentrate on the case in which the electroweak symmetry breaking sector is strongly interacting and there are no new resonances within reach of the collider. We find a sensitivity to the anomalous couplings that is two orders of magnitude higher than that achievable at LEP II. We also show how a polarized electron beam extends the reach of the collider, allowing experiments to probe different directions in parameter space.Comment: 21 pages LaTeX, epsf figure

Effect of pH of amine fluoride containing toothpastes on enamel remineralization in vitro

<p>Abstract</p> <p>Background</p> <p>One of the important factors of the demineralization and remineralization equilibrium of enamel is the pH of the surrounding solutions. Effort has been laid in the formulation of different fluoride compounds and the fluoride content in toothpastes but much less is known about the influence of the pH of the toothpastes on their effectiveness. It was therefore the aim of this study to investigate the influence of different pH levels on enamel remineralization in an in vitro experiment using polarization light microscopy and EDX quantitative element analysis.</p> <p>Methods</p> <p>A 5 × 5 mm window on the enamel surface of 40 caries free extracted human premolars was demineralized in a hydroxyethylcellulose solution at pH 4.8. The teeth were divided into 8 groups and the lower half of the window was covered with varnish serving as control. Each group was then immersed in toothpaste slurry containing amine fluoride (1400 ppm) at pH 4.1, 4.5, 5.1 and 6.9 or control toothpaste slurry without fluoride at pH 4.3, 4.7, 5.3 and 7.0. Serial sections were cut through the lesions and investigated with polarization light microscopy and quantitative EDX element analysis.</p> <p>Results</p> <p>The PLM results showed a decreased porous volume of the body of the lesion after incubation with fluoridated toothpaste at pH 4.53 and 5.16. No differences between the experimental window and the control window were found in the other groups. The quantitative element analysis showed no differences in the element content of any of the groups.</p> <p>Conclusion</p> <p>From the results it can be concluded that slightly acidified fluoridated dentifrices may have a certain positive effect on enamel remineralization.</p

Probing nonstandard bosonic interactions via W-boson pair production at lepton colliders

The process e+e- --> W+W- provides a valuable laboratory to test the Standard Model (SM) and to search for new physics. The most general helicity amplitudes for this process require the introduction of nine form-factors which we calculate in the context of SU(2) X U(1) gauge-invariant extensions of the SM. The contributions of new physics are parametrized via an effective Lagrangian constructed from the light fields. Because the mechanism of electroweak symmetry-breaking remains an open problem we consider both the effective Lagrangian with a linearly realized Higgs sector, i.e. with a light physical Higgs boson, and the effective Lagrangian which utilizes a nonlinear realization of the Higgs mechanism. The use of an effective Lagrangian allows one to calculate consistently nonstandard contributions to e+e- --> W+W- amplitudes as well as the nonstandard contributions to other processes. We study the interplay of the low-energy and Z-pole measurements with measurements via the processes e+e- --> fermion pairs and e+e- --> W+W- at LEP II or a future linear e+e- collider. Concrete relationships between operators of the linear and nonlinear realizations are presented where possible.Comment: \documentstyle[aps,floats,psfig,subeqn,rotate,eqsecnum]{revtex} postscript version also available from ftp://ftp.kek.jp/kek/preprints/TH/TH-49