Prospects for new physics observations in diffractive processes at the LHC and Tevatron

We study the double-diffractive production of various heavy systems (e.g. Higgs, dijet, and SUSY particles) at LHC and Tevatron collider energies. In each case we compute the probability that the rapidity gaps, which occur on either side of the produced system, survive the effects of soft rescattering and QCD bremsstrahlung effects. We calculate both the luminosity for different production mechanisms, and a wide variety of subprocess cross sections. The results allow numerical predictions to be readily made for the cross sections of all these processes at the LHC and the Tevatron collider. For example, we predict that the cross section for the exclusive double-diffractive production of a 120 GeV Higgs boson at the LHC is about 3 fb, and that the QCD background in the decay mode is about 4 times smaller than the Higgs signal if the experimental missing-mass resolution is 1 GeV. For completeness we also discuss production via or WW fusion. Received: 7 November 2001 / Revised version: 11 December 2001 / Published online: 25 January 2002     

Study of the Surface Processes in Vapor-Phase Epitaxial GaAs: Asymmetric Trapping of Atoms at the Step

Experimental proofs of asymmetric trapping of atoms at the growth step in vapor-phase epitaxy of gallium arsenide in the GaAs–AsCl₃–H₂ system are given. The data obtained confirm the important role of the surface diffusion mass transfer in the growth of epitaxial GaAs layers on vicinals in the neighborhood of (111)A. The effective diffusion length is estimated.     

Luttinger liquid with asymmetric dispersion

We present an extension of the Tomonaga-Luttinger model in which left and right-moving particles have different Fermi velocities. We derive expressions for one-particle Green's functions, momentum-distributions, density of states, charge compressibility and conductivity as functions of both the velocity difference ε and the strength of the interaction β. This allows us to identify a novel restricted region in the parameter space in which the system keeps the main features of a Luttinger liquid but with an unusual behavior of the density of states and the static charge compressibility κ. In particular κ diverges on the boundary of the restricted region, indicating the occurrence of a phase transition. Received 20 May 2002 / Received in final form 23 August 2002 Published online 19 November 2002     

Structure and properties of porous silicon obtained by photoanodization

The results of an investigation of layers of porous silicon (PS), which was obtained by electrochemical etching of p-Si under different illumination conditions — natural light, incandescent light, and light from a mercury lamp with and without a filter — are reported. The structure of the layers was studied by double-crystal x-ray diffractometry, the composition was monitored by means of the IR absorption spectra, and the radiative properties were monitored according to the photoluminescence (PL) spectra. It was established that electrochemical etching under illumination produces PS with a higher porosity and more intense PL whose maximum is shifted into the short-wavelength region. These changes are accompanied by a large disordering of the structure and an increase in the oxygen content in the layer. It is concluded that illumination accelerates the chemical interaction of PS with the electrolyte due to oxidation. High-porosity porous silicon stored in air exhibits quenching of PL. Conversely, PL is excited in layers with a lower porosity. Aging of PS is characterized by an increase in the microdeformation of the layers, a decrease in the crystallite sizes with a partial loss of coherence between the crystallites and the substrate, and an increase in the fraction of the amorphous phase. Fiz. Tekh. Poluprovodn. 31, 1261–1268 (October 1997)     

A planar XeCl-exilamp pumped by a low-pressure glow discharge

The energy characteristics of an XeCl exciplex lamp with planar construction pumped by a low-pressure gas discharge are investigated experimentally. When a discharge gap of width 2 cm and a Xe-Cl₂ mixture were used, average radiation powers up to 20 mW were obtained in the wavelength interval 200–380 nm at efficiencies of ∼0.4%. In this case the total efficiency of radiation into an angle of 4π exceeded 4%. It is shown that increasing the working pressure and using low discharge currents can lead to “point” radiation sources. Zh. Tekh. Fiz. 67, 43–46 (December 1997)     

Diurnal thermal cycling effects on microwave signatures of thin seaice

To investigate effects of diurnal thermal cycles on C-band polarimetric backscatter and millimeter-wave emission from sea ice, the authors carried out a winter experiment at the outdoor geophysical research facility (GRF) in the cold regions research and engineering laboratory (CRREL), the ice sheet grew from open sea water to a thickness of 10 cm in 2.5 days, during which they took polarimetric backscatter data with a C-band scatterometer, interlaced with brightness temperature measurements at 90 GHz in conjunction with meteorological and sea ice characterizations. The initial ice growth in the late morning was slow due to high insolation. As the air temperature dropped during the night, the growth rate increased significantly. Air temperature changed drastically from about -12 to -36°C between day and night, the diurnal thermal cycle repeated itself the next day and the growth rate varied in the same manner. Ice temperature profiles clearly show the diurnal response in the ice sheet with a lag of 2.5 h behind the time of the maximum short-wave incident solar radiation. The diurnal cycles are also evident in the millimeter-wave brightness temperature data, measured sea ice backscatter revealed substantial diurnal variations up to 6 dB with repeatable cycles in synchronization with the temperature cycles and the brightness temperature modulations, the diurnal cycles in backscatter indicate that the dominant scattering mechanism related to thermodynamic processes in sea ice is reversible, a diurnal backscatter model based on sea ice electrodynamics and thermodynamics explains the observed diurnal signature. This work shows that diurnal effects are important for inversion algorithms to retrieve sea ice geophysical parameters from remote sensing data acquired with a satellite synthetic aperture radar (SAR) or scatterometer on Sun-synchronous orbits     

Investigation of iron borate on the submillimeter waves

Antiferromagnetic resonance (AFMR) in iron borate at the frequency of 300 GHz at the room temperature in weak (down to 0.1T) external magnetic fieldH has been studied. The loss in AFMR line increased or decreased depending on the direction and magnitude ofH. Such properties ofFeBO ₃ monocrystals allows to design undirectional and modulation devices.     

A Green's function method of determining the residual stresses in cylindrical glass shells

We propose a way of modifying the mathematical model of the nondestructive theoretical-experimental method of determining the residual stresses for a specific collection of technological conditions for welding two cylindrical glass shells. The method is based on the general theory of boundary-value problems for ordinary differential equations.Translated fromMatematicheskie Metody i Fiziko-Mekhanicheskie Polya, Issue 33, 1991, pp. 69–73.     

Database reverse engineering: From requirements to CARE tools

This paper analyzes the requirements that CASE tools should meet for effective database reverse engineering (DBRE), and proposes a general architecture for data-centered applications reverse engineering CASE environments. First, the paper describes a generic DBMS-independent DBRE methodology, then it analyzes the main characteristics of DBRE activities in order to collect a set of desirable requirements. Finally, it describes DB-MAIN, an operational CASE tool developed according to these requirements. The main features of this tool that are described in this paper are its unique generic specification model, its repository, its transformation toolkit, its user interface, the text processors, the assistants, the methodological control and its functional extensibility. Finally, the paper describes five real-world projects in which the methodology and the CASE tool were applied. This is a heavily revised and extended version of “Requirements for Information System Reverse Engineering Support” by J.-L. Hainaut, V. Englebert, J. Henrard, J.-M. Hick, D. Roland, which first appeared in the Proceedings of the Second Working Conference on Reverse Engineering, IEEE Computer Society Press, pp. 136–145, July 1995. This paper presents some results of the DB-MAIN project. This project is partially supported by the Région Wallonne, the European Union, and by a consortium comprising ACEC-OSI (Be), ARIANE-II (Be), Banque UCL (Lux), BBL (Be), Centre de recherche public H. Tudor (Lux), CGER (Be), Cockerill-Sambre (Be), CONCIS (Fr), D'Ieteren (Be), DIGITAL, EDF (Fr), EPFL (CH), Groupe S (Be), IBM, OBLOG Software (Port), ORIGIN (Be), Ville de Namur (Be), Winterthur (Be), 3 Suisses (Be). The DB-Process subproject is supported by the Communauté Fran?aise de Belgique.