Soliton-antisoliton pair production in particle collisions

We propose general semiclassical method for computing the probability of soliton-antisoliton pair production in particle collisions. The method is illustrated by explicit numerical calculations in (1+1)-dimensional scalar field model. We find that the probability of the process is suppressed by an exponentially small factor which is almost constant at high energies.Comment: 4 pages, 3 figures, journal versio

Particle decay in false vacuum

We revisit the problem of decay of a metastable vacuum induced by the presence of a particle. For the bosons of the `master field' the problem is solved in any number of dimensions in terms of the spontaneous decay rate of the false vacuum, while for a fermion we find a closed expression for the decay rate in (1+1) dimensions. It is shown that in the (1+1) dimensional case an infrared problem of one-loop correction to the decay rate of a boson is resolved due to a cancellation between soft modes of the field. We also find the boson decay rate in the `sine-Gordon staircase' model in the limits of strong and weak coupling.Comment: 19 pages, 2 figure

Інформаційна система обліку як спосіб зменшення невизначеності на ринку будівельних послуг (Information system of accounting as a way to reduce uncertainty on the market building services)

(У статті розглянуто можливість використання автоматизованої інформаційної системи для обліку робіт будівельного підприємства. Виділено проблему формування бази даних такої системи, яка полягає у відсутності повної автоматизації процесів збору, пошуку, оброблення та аналізу інформації. Виокремлено інформаційні та інші зв’язки будівельного підприємства з зовнішніми об’єктами, зокрема замовниками, розробниками проектів, виробниками. Зображено функціональну структуру інформаційної системи обліку будівельних послуг. На основі сформованих вимог та обмежень до системи побудовано її логічно-інформаційну модель. Описано основні елементи інтерфейсу автоматизованої інформаційної системи для обліку робіт будівельного підприємства.) Consider the possibility use an automated information system for account of the work of the building enterprise. Secrete the problem of forming a database of such system, which has the absence of full automation of the processes of collection, retrieval, processing and analysis of information. Exude information contacts and other contacts of building enterprise with external objects, including customers, project developers and manufacturers. Depicted functional structure of information system of accounting of building services. Constructed logical model of information system based on existing requirements and limitations to the system. Described the basic elements of interface of automated information system for accounting work building enterprise.

New analysis of semileptonic B decays in the relativistic quark model

We present the new analysis of the semileptonic B decays in the framework of the relativistic quark model based on the quasipotential approach. Decays both to heavy D^{(*)} and light \pi(\rho) mesons are considered. All relativistic effects are systematically taken into account including contributions of the negative-energy states and the wave function transformation from the rest to moving reference frame. For heavy-to-heavy transitions the heavy quark expansion is applied. Leading and subleading Isgur-Wise functions are determined as the overlap integrals of initial and final meson wave functions. For heavy-to-light transitions the explicit relativistic expressions are used to determine the dependence of the form factors on the momentum transfer squared. Such treatment significantly reduces theoretical uncertainties and increases reliability of obtained predictions. All results for form factors, partial and total decay rates agree well with recent experimental data and unquenched lattice calculations. From this comparison we find the following values of the Cabibbo-Kobayashi-Maskawa matrix elements: |V_{cb}|=(3.85\pm0.15\pm 0.20)*10^{-2} and |V_{ub}|=(3.82\pm0.20\pm0.20)*10^{-3}, where the first error is experimental and the second one is theoretical.Comment: 25 pages, 11 figure

Strong and radiative decays of the Ds0*(2317) meson in the DK-molecule picture

We consider a possible interpretation of the new charm-strange meson Ds0*(2317) as a hadronic molecule - a bound state of D and K mesons. Using an effective Lagrangian approach we calculate the strong Ds0* to Ds pi0 and radiative Ds0* to Ds* gamma decays. A new impact related to the DK molecular structure of the Ds0*(2317) meson is that the presence of u(d) quarks in the D and K mesons gives rise to a direct strong isospin-violating transition Ds0* to Ds pi0 in addition to the decay mechanism induced by eta-pi0 mixing considered previously. We show that the direct transition dominates over the eta-pi0 mixing transition in the Ds0* to Ds pi0 decay. Our results for the partial decay widths are consistent with previous calculations.Comment: 22 pages, 4 figures, accepted for publication in Phys. Rev.

Neutrino scattering on atomic electrons in searches for neutrino magnetic moment

The scattering of a neutrino on atomic electrons is considered in the situation where the energy transferred to the electrons is comparable to the characteristic atomic energies, as relevant to the current experimental search for neutrino magnetic moment. The process is contributed by the standard electroweak interaction as well as by the possible neutrino magnetic moment. Quantum mechanical sum rules are derived for the inclusive cross section at a fixed energy deposited in the atomic system, and it is shown that the differential over the energy transfer cross section is given, modulo very small corrections, by the same expression as for free electrons, once all possible final states of the electronic system are taken into account. Thus the atomic effects effectively cancel in the inclusive process.Comment: 7 pages. A clarifying illustrative example adde