203 research outputs found
Nonlinear acoustic waves in channels with variable cross sections
The point symmetry group is studied for the generalized Webster-type equation
describing non-linear acoustic waves in lossy channels with variable cross
sections. It is shown that, for certain types of cross section profiles, the
admitted symmetry group is extended and the invariant solutions corresponding
to these profiles are obtained. Approximate analytic solutions to the
generalized Webster equation are derived for channels with smoothly varying
cross sections and arbitrary initial conditions.Comment: Revtex4, 10 pages, 2 figure. This is an enlarged contribution to
Acoustical Physics, 2012, v.58, No.3, p.269-276 with modest stylistic
corrections introduced mainly in the Introduction and References. Several
typos were also correcte
Влияние освещения кризиса на финансовый рынок России
The article examines the impact of informational messages characterizing the crisis in the economy on the financial market indicators. The aim of the article is to build an index that allows assessing the crisis situation in the country based on textual analysis of informational messages. Due to the literature review, the factors determining the crisis in the economy were identified. The empirical base of the study included more than 10 million news texts from various sources accredited by Thomson Reuters. For the first time, the authors compiled a “bag of words” (dictionary) to determine the crisis situation in the country; and by means of the text analysis, they developed the author’s crisis index calculated on the basis of news reports in foreign media about Russia. They conducted the analysis of the relations between the crisis index and the stock index MOEX. According to the results of the study, it has been established that an increase in the number of news reports determining the crisis situation in the economy has a negative effect on the financial market: it leads to a drop in stock prices. Thus, not only objective economic factors, but also the information component influencing the mood of investors and the behavior of economic entities, affects the key indicators of the financial market. The proposed author’s crisis index can also be used to assess other relations, for example, the effect of the crisis on the exchange rate.В статье исследуется влияние информационных сообщений, характеризующих проявление кризиса в экономике, на показатели финансового рынка. Цель статьи — построение индекса, позволяющего оценивать кризисную ситуацию в стране на основе текстового анализа информационных сообщений. С помощью обзора литературы выявлены факторы, определяющие кризисные явления в экономике. Эмпирическая база исследования включала в себя более 10 млн новостных текстов из различных источников, аккредитованных ThomsonReuters. Авторы впервые составили «мешок слов» (словарь) для определения кризисной ситуации в стране и с помощью текстового анализа разработали авторский индекс кризиса, рассчитанный на основе новостных сообщений в зарубежных СМИ о России. Проведен анализ зависимости между индексом кризиса и биржевым индексом MOEX. По результатам исследования установлено, что увеличение количества новостных сообщений, определяющих проявление кризисной ситуации в экономике, негативно отражается на финансовом рынке: приводит к падению котировок акций. Таким образом, не только объективные экономические факторы, но и информационная составляющая, оказывающая влияние на настроения инвесторов и поведение экономических субъектов, воздействует на ключевые показатели финансового рынка. Предложенный авторский индекс кризиса может также быть использован для оценки других зависимостей, например влияния кризиса на валютный курс
A Precise Measurement of the Muon Neutrino-Nucleon Inclusive Charged Current Cross-Section off an Isoscalar Target in the Energy Range 2.5 < E_\nu < 40 GeV by NOMAD
We present a measurement of the muon neutrino-nucleon inclusive charged
current cross-section, off an isoscalar target, in the neutrino energy range
GeV. The significance of this measurement is its
precision, % in GeV, and % in GeV regions, where significant uncertainties in previous
experiments still exist, and its importance to the current and proposed long
baseline neutrino oscillation experiments.Comment: 14 pages, 3 figures, submitted to Phys.Lett.
A Measurement of Coherent Neutral Pion Production in Neutrino Neutral Current Interactions in NOMAD
We present a study of exclusive neutral pion production in neutrino-nucleus
Neutral Current interactions using data from the NOMAD experiment at the CERN
SPS. The data correspond to muon-neutrino Charged Current
interactions in the energy range GeV. Neutrino
events with only one visible in the final state are expected to result
from two Neutral Current processes: coherent production, {\boldmath
} and single production in
neutrino-nucleon scattering. The signature of coherent production is an
emergent almost collinear with the incident neutrino while 's
produced in neutrino-nucleon deep inelastic scattering have larger transverse
momenta. In this analysis all relevant backgrounds to the coherent
production signal are measured using data themselves. Having determined the
backgrounds, and using the Rein-Sehgal model for the coherent
production to compute the detection efficiency, we obtain {\boldmath } corrected coherent- events with GeV. We measure {\boldmath }.
This is the most precise measurement of the coherent production to
date.Comment: 23 pages, 9 figures, accepted for publication in Phys. Lett.
Final NOMAD results on nu_mu->nu_tau and nu_e->nu_tau oscillations including a new search for nu_tau appearance using hadronic tau decays
Results from the nu_tau appearance search in a neutrino beam using the full
NOMAD data sample are reported. A new analysis unifies all the hadronic tau
decays, significantly improving the overall sensitivity of the experiment to
oscillations. The "blind analysis" of all topologies yields no evidence for an
oscillation signal. In the two-family oscillation scenario, this sets a 90%
C.L. allowed region in the sin^2(2theta)-Delta m^2 plane which includes
sin^2(2theta)<3.3 x 10^{-4} at large Delta m^2 and Delta m^2 < 0.7 eV^2/c^4 at
sin^2(2theta)=1. The corresponding contour in the nu_e->nu_tau oscillation
hypothesis results in sin^2(2theta)<1.5 x 10^{-2} at large Delta m^2 and Delta
m^2 < 5.9 eV^2/c^4 at sin^2(2theta)=1. We also derive limits on effective
couplings of the tau lepton to nu_mu or nu_e.Comment: 46 pages, 16 figures, Latex, to appear on Nucl. Phys.
Prediction of Neutrino Fluxes in the NOMAD Experiment
The method developed for the calculation of the flux and composition of the
West Area Neutrino Beam used by NOMAD in its search for neutrino oscillations
is described. The calculation is based on particle production rates computed
using a recent version of FLUKA and modified to take into account the cross
sections measured by the SPY and NA20 experiments. These particles are
propagated through the beam line taking into account the material and magnetic
fields they traverse. The neutrinos produced through their decays are tracked
to the NOMAD detector. The fluxes of the four neutrino flavours at NOMAD are
predicted with an uncertainty of about 8% for nu(mu) and nu(e), 10% for
antinu(mu), and 12% for antinu(e). The energy-dependent uncertainty achieved on
the R(e, mu) prediction needed for a nu(mu)->nu(e) oscillation search ranges
from 4% to 7%, whereas the overall normalization uncertainty on this ratio is
4.2%.Comment: 43 pages, 20 figures. Submitted to Nucl. Phys.
Inclusive production of and mesons in charged current interactions
The inclusive production of the meson resonances ,
and in neutrino-nucleus charged current interactions has been
studied with the NOMAD detector exposed to the wide band neutrino beam
generated by 450 GeV protons at the CERN SPS. For the first time the
meson is observed in neutrino interactions. The statistical
significance of its observation is 6 standard deviations. The presence of
in neutrino interactions is reliably established. The average
multiplicity of these three resonances is measured as a function of several
kinematic variables. The experimental results are compared to the
multiplicities obtained from a simulation based on the Lund model. In addition,
the average multiplicity of in antineutrino - nucleus
interactions is measured.Comment: 23 pages, 14 figures, 8 tables. To appear in Nucl. Phys.
Search for nu(mu)-->nu(e) Oscillations in the NOMAD Experiment
We present the results of a search for nu(mu)-->nu(e) oscillations in the
NOMAD experiment at CERN. The experiment looked for the appearance of nu(e) in
a predominantly nu(mu) wide-band neutrino beam at the CERN SPS. No evidence for
oscillations was found. The 90% confidence limits obtained are delta m^2 < 0.4
eV^2 for maximal mixing and sin^2(2theta) < 1.4x10^{-3} for large delta m^2.
This result excludes the LSND allowed region of oscillation parameters with
delta m^2 > 10 eV^2.Comment: 19 pages, 8 figures. Submitted to Phys. Lett.
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