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The paper proposes an approximate expression for calculating very complex one-dimensional integrals depending on the parameter $a$. These integrals often occur in computational problems theory of magnetic solitons. The resulting analytical expressions are verified by numerical calculation. The comparison shows that the relative accuracy of the approximating expression tends to zero for large and small values of the parameter $a$. In a small region near $a = 0.119$, the error does not exceed five percent, and for parameter values near $18.0$ the relative error does not exceed seven percent. It turned out that the proposed method of constructing approximating expressions can be generalized to much more complex integrals. A program that compares an approximate expression with an exact numerical value written in C and tested on examples that allow analytical solutions., Comment: 8 pages, 2 figures

Using the density matrix formalism, we prove an existence theorem of the periodic steady-state for an arbitrary periodically-driven system. This state has the same period as the modulated external influence, and it is realized as an asymptotic solution ($t$$\to$$+\infty$) due to relaxation processes. The presented derivation simultaneously contains a simple computational algorithm non-using both Floquet and Fourier theories, i.e. our method automatically guarantees a full account of all frequency components. The description is accompanied by the examples demonstrating a simplicity and high efficiency of our method. In particular, for three-level $\Lambda$-system we calculate the lineshape and field-induced shift of the dark resonance formed by the field with periodically modulated phase. For two-level atom we obtain the analytical expressions for signal of the direct frequency comb spectroscopy with rectangular light pulses. In this case it was shown the radical dependence of the spectroscopy lineshape on pulse area. Moreover, the existence of quasi-forbidden spectroscopic zones, in which the Ramsey fringes are significantly reduced, is found. The obtained results have a wide area of applications in the laser physics and spectroscopy, and they can stimulate the search of new excitation schemes for atomic clock. Also our results can be useful for many-body physics., Comment: 8 pages, 8 figures

The Enriched Xenon Observatory (EXO) will search for double beta decays of 136Xe. We report the results of a systematic study of trace concentrations of radioactive impurities in a wide range of raw materials and finished parts considered for use in the construction of EXO-200, the first stage of the EXO experimental program. Analysis techniques employed, and described here, include direct gamma counting, alpha counting, neutron activation analysis, and high-sensitivity mass spectrometry., Comment: 32 pages, 6 figures. Expanded introduction, added missing table entry. Accepted for publication in Nucl. Instrum. Meth. A

CompHEP is a package for automatic calculations of elementary particle decay and collision properties in the lowest order of perturbation theory (the tree approximation). The main idea prescribed into the CompHEP is to make available passing on from the Lagrangian to the final distributions effectively with a high level of automation., Comment: 126 pages (standard LaTeX code), 14 figures, misprints improved

We discuss the SM Higgs discovery potential of LHC in the reaction $pp\to H+ jet\to\gamma\gamma+jet$ when the jet is observed at sufficiently high $E_t$ to be reliably identified. We conclude that this channel gives promising discovery possibilities for the Higgs boson mass range 100-140 GeV, during LHC operation at a low luminosity. With 30 fb$^{-1}$ of accumulated data and for $M_H=120$ GeV about 100 signal events could be observed with the number of background events larger by a factor of 2 only, showing a signal significance $S/\sqrt{B}\sim 7$. We use the difference of distributions in the partonic subprocess energy $\sqrt{\hat s}$ for the signal and background for a better separation of the signal., Comment: 15 pages including 6 figures, LaTeX, use epsfig.sty. To appear in Phys.Lett.B. In this replacement minor LaTeX improvements are made

We present the results of calculations for the process gamma gamma -> W + 2 fermions at a future Photon Linear Collider (PLC). The calculations include at the same time the next-to-leading order Higgs signal and the complete tree level gauge boson background. We present numerical results in the intermediate mass Higgs region 140 GeV < M_H < 2M_W. We propose strategies for the determination of Higgs properties using the leptonic and hadronic final states for both polarized and unpolarized photon beams., Comment: 14 pages, LaTeX (using amsmath.sty), 4 EPS figures included

The CompHEP package was developed for calculations of decay and high energy collision processes with, correspondingly, up to 5 and 4 final particles in the lowest order (tree) approximation. The main idea put into CompHEP was to make available passing from the Lagrangian to final distributions efficiently with high level automation what is extremely needed in collider physics. The present talk describes a general structure of the CompHEP facilities and reports some physical results obtained with its help. The main purpose of the talk is to attract the attention of high energy physicists to this user-friendly package which is completely aimed at making easier their routine and tedious calculations in the TeV region., Comment: 18 pages, standard LaTeX code, uses epsf macros; 13 figures (uses 11 files in PS and EPS formats). Talk presented at the Xth Workshop on High Energy Physics and Quantum Field Theory (20-26 September 1995, Zvenigorod, Russia). The code of CompHEP package is available at http://theory.npi.msu.su/~pukhov/comphep.html

We describe an algorithm for the generation of relativistic kinematics for collision and decay processes with multiparticle final states. In the framework of this algorithm it is possible to generate different kinematics covering most of practically interesting cases. One gets a possibility to introduce different sets of integration variables. As a result different sets of kinematical singularities can be regularized. To smooth sharp peaks some regularization formulas and procedures are used covering most typical cases. The algorithm is realized in the package CompHEP created for automatic calculations of collision and decay processes., Comment: 10 pages, standard LaTeX code