52 research outputs found
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
Dimension-six top-Higgs interaction and its effect in collider phenomenology
Measurement of the Yukawa interaction between the top quark and the Higgs
boson should be useful to clarify the mechanism of fermion mass generation.
We discuss the impact of non-standard interactions characterized by
dimension-six operators on the effective top Yukawa coupling.
The cross section of the process is calculated including these operators, and possible deviation
from the standard model prediction is evaluated under the constraint from
perturbative unitarity and current experimental data.
We find that if the new physics scale is in a TeV region, the cross section
can be significantly enhanced due to the non-standard interactions.
Such a large effect should be detectable at the International Linear
Collider.Comment: 22 pages, RevTex4, 20 eps figure
The Measurement of Tri-Linear Gauge Boson Couplings at Colliders
We describe a detailed study of the process and the measurement of tri-linear gauge boson couplings (TGV's) at
LEP200 and at a 500~GeV and 1~TeV NLC. We included all tree level Feynman
diagrams contributing to the four-fermion final states including gauge boson
widths and non-resonance contributions. We employed a maximum likelihood
analysis of a five dimensional differential cross section of angular
distributions. This approach appears to offer an optimal strategy for
measurement of TGV's. LEP200 will improve existing measurements of TGV's but
not enough to see loop contributions of new physics. Measurements at the NLC
will be roughly 2 orders of magnitude more precise which would probe the
effects of new physics at the loop level.Comment: Latex file uses aipbook.sty with revtex and psfig.sty. 2 figures
(uuencoded) will be added with figures command. Full postcript version with
embedded figures is available at
ftp://ftp.physics.carleton.ca/pub/theory/godfrey/ocipc9504.ps To appear in
the Proceedings of the International Symposium on Vector Boson
Self-Interactions, UCLA, Feb. 1-3, 199
The Kolmogorov-Smirnov test and its use for the identification of fireball fragmentation
We propose an application of the Kolmogorov-Smirnov test for rapidity
distributions of individual events in ultrarelativistic heavy ion collisions.
The test is particularly suitable to recognise non-statistical differences
between the events. Thus when applied to a narrow centrality class it could
indicate differences between events which would not be expected if all events
evolve according to the same scenario. In particular, as an example we assume
here a possible fragmentation of the fireball into smaller pieces at the
quark/hadron phase transition. Quantitative studies are performed with a Monte
Carlo model capable of simulating such a distribution of hadrons. We conclude
that the Kolmogorov-Smirnov test is a very powerful tool for the identification
of the fragmentation process.Comment: 9 pages, 10 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
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