The specificity of searches for W′W^{\prime}, Z′Z^{\prime} and γ′\gamma^{\prime} coming from extra dimensions

We discuss the specificity of searches for hypothetical $W^{\prime}$, $Z^{\prime}$ and $\gamma^{\prime}$ bosons at hadron colliders in single top quark and $\mu^{+}\nu_{\mu}$ production and Drell-Yan processes assuming these particles to be the Kaluza-Klein excitations of the gauge bosons of the Standard Model. In this case any process mediated by $W$ is also mediated by the whole KK tower of its excitations, whereas to the processes mediated by $Z$ and $\gamma$ there is not only a contribution from their KK towers, but also from that of the graviton. The contributions of the towers above $W^{\prime}$, $Z^{\prime}$ and $\gamma^{\prime}$ and above the first excitation of the graviton are included with the help of effective four-fermion Lagrangians. We compute the cross-sections of these processes taking into account the contributions of the Standard Model gauge bosons, of their first KK modes and of the corresponding KK towers and discuss the impact of the interference between them. For pp-collisions at the LHC with the center of mass energy 14 TeV we found specific changes of the distribution tails due to the interference effects. Such a modification of distribution tails is characteristic for the processes mediated by particles coming from extra dimensions and should always be taken into account when looking for them.Comment: 14 pages, 12 figures, LaTeX. References added, figures added, text enlarge

A non-standard matter distribution in the RS1 model and the coupling constant of the radion

In the zero mode approximation we solve exactly the equations of motion for linearized gravity in the Randall-Sundrum model with a non-standard distribution of matter in the neighbourhood of the negative tension brane. It is shown that the form of this distribution can strongly affect the coupling of the radion to matter. We believe that such a situation can arise in models with a realistic mechanisms of matter localization.Comment: 12 pages, LaTe

Stratification of the orbit space in gauge theories. The role of nongeneric strata

Gauge theory is a theory with constraints and, for that reason, the space of physical states is not a manifold but a stratified space (orbifold) with singularities. The classification of strata for smooth (and generalized) connections is reviewed as well as the formulation of the physical space as the zero set of a momentum map. Several important features of nongeneric strata are discussed and new results are presented suggesting an important role for these strata as concentrators of the measure in ground state functionals and as a source of multiple structures in low-lying excitations.Comment: 22 pages Latex, 1 figur

Effective Lagrangians for physical degrees of freedom in the Randall-Sundrum model

We derive the second variation Lagrangian of the Randall-Sundrum model with two branes, study its gauge invariance and diagonalize it in the unitary gauge. We also show that the effective four-dimensional theory looks different on different branes and calculate the observable mass spectra and the couplings of the physical degrees of freedom of 5-dimensional gravity to matter.Comment: 22 pages, LaTeX, typos correcte

With Phenotypic Signs of Connective Tissue Dysplasia: Cross-Sectional Clinical Study

Background. The dental health is an integral part of a person's well-being. Students of higher educational institutions comprise a health risk group, since they experience extensive physiological changes and personal socialization. The impact of connective tissue dysplasia on dental health is a relevant research task.Objective. To analyze the correlation between dental pathology and phenotypic signs of connective tissue dysplasia in first-year students.Methods. A cross-sectional clinical study of the dental health and phenotypic signs of connective tissue dysplasia was conducted as part of routine dental examination of 263 first-year students of KubSMU, aged 18–23. All participants were divided into 2 groups: group 1 – participants with 0-2 signs of connective tissue dysplasia (n = 108); group 2 – participants with 3 or more signs of dysplasia (n = 155). Statistical analysis of the results was carried out using Microsoft Excel 2010 and Statistica 6.0.Results. Unsatisfactory and poor oral hygiene levels in the group of participants with connective tissue dysplasia outnumber these levels in the control group by 30% and 22%, with very poor level in the second group 2.3 times higher (p ≤ 0.05). The incidence of noncarious tooth pathology in individuals with dysplasia is 26% higher than in the control group. The caries intensity index in group 2 is almost 20% bigger than in the control group. As expected, the group of participants with no signs of dysplasia revealed better periodontal health, namely 51.85% versus 45.81% (p ≤ 0.05). In terms of mucosal pathology, a statistical significant difference between groups 1 and 2 was noted for traumatic injuries (16.35% and 19.35%, respectively). Dentofacial abnormalities were observed more often in individuals with 3 or more phenotypic signs of connective tissue dysplasia.Conclusion. Higher morbidity rate of caries and noncarious pathology in the group of first-year students with 3 or more phenotypic signs of connective tissue dysplasia, compared to the group with 0–2 phenotypic manifestations of dysplasia, indicated the need to create a database of the dentofacial profiles of students, develop an algorithm for regular medical check-up of students, as well as provide differentiated preventive and therapeutic measures for students with dysplasia

ENVIRONMENTALLY FRIENDLY METHOD OF GASEOUS FUEL COMBUSTION WITH THE USE OF QUASI-OPTICAL MICROWAVE

Subject of Research.The paper deals with the problem of developing low emission combustors operating on natural gas or LPG, to reduce emissions of nitrogen oxides NOx. The possibility of burning very lean fuel mixtures is studied. To initiate the ignition and combustion stabilization the discharge generated by the quasi-optical microwave is used. Main Results. Initiating ignition by streamer microwave discharge increases the rate of combustion and combustion efficiency about four times as compared with the conventional spark ignition. Streamer discharge ignition by very lean fuel-air mixture is demonstrated with the factor of oxiding agent excess greater than the limit of explosive range under normal conditions. According to indirect indicators, ignition by microwave discharge created by quasi-optical radiation is of non-thermal nature. Microwave discharge excites oxygen atoms, and intense ultra-violet radiation is generated as a result that causes formation of cold nonequilibrium plasma with avalanche growth of free electrons. Streamer discharge propagates at a speed of 5 km /s, so the initiation of the ignition occurs immediately throughout. The temperature of the fuel mixture at the point of ignition initiation does not exceed 400 К.There is no area with a temperature sufficient to initiate thermal Zeldovich mechanism of emission of nitrogen oxides. Combustion rate is high. As a result the Fenimore mechanism of "fast nitrogen oxides" has no chance to be progressing, and NOx emissions in appreciable quantities are excluded. Energy costs are comparable with spark ignition.Practical Relevance. The studied technology is designed for low emission internal combustion engines, power gas turbines, gas compressor units, fueled by natural gas

Braneworlds in six dimensions: new models with bulk scalars

Six dimensional bulk spacetimes with 3-- and 4--branes are constructed using certain non--conventional bulk scalars as sources. In particular, we investigate the consequences of having the phantom (negative kinetic energy) and the Brans--Dicke scalar in the bulk while obtaining such solutions. We find geometries with 4--branes with a compact on--brane dimension (hybrid compactification) which may be assumed to be small in order to realize a 3--brane world. On the other hand, we also construct, with similar sources, bulk spacetimes where a 3--brane is located at a conical singularity. Furthermore, we investigate the issue of localization of matter fields (scalar, fermion, graviton, vector) on these 3-- and 4--branes and conclude with comments on our six dimensional models.Comment: 24 pages, 1 figure, Replaced to match version published in Class. Quant. Gra

Ion and Electron Momentum Distributions from Single and Double Ionization of Helium Induced by Compton Scattering

We present the momentum distributions of the nucleus and of the electrons from double ionization of the helium atom by Compton scattering of photons with hν=40  keV. We find that the doubly charged ion momentum distribution is very close to the Compton profile of the nucleus in the ground state of the helium atom, and the momentum distribution of the singly charged ion to give a precise image of the electron Compton profile. To reproduce these results, nonrelativistic calculations require the use of highly correlated initial- and final-state wave functions