101 research outputs found
Nonperturbative and spin effects in the central exclusive production of tensor meson
We discuss central exclusive production (CEP) of the tensor
meson in proton-(anti)proton collisions at Tevatron, RHIC and LHC energies. The
amplitude for the process is derived within the -factorisation approach.
Differential and total cross sections are calculated for several unintegrated
gluon distributions (UGDFs). We compare exclusive production of all charmonium
states and . Equally good description
of the recent Tevatron data is achieved both with Martin-Ryskin
phenomenological UGDF and UGDF based on unified BFKL-DGLAP approach. Unlike for
Higgs production, the main contribution to the diffractive amplitude of heavy
quarkonia comes from nonperturbative region of gluon transverse momenta
Q_{\perp}<1\,\GeV. At 0, depending on UGDF we predict the
contribution of to the channel to be
comparable or larger than that of the one. This is partially due
to a significant contribution from lower polarization states for
and for meson. Corresponding
theoretical uncertainties are discussed.Comment: 18 pages, 12 figures, discrepancies with Durham group results
clarified, numerics corrected, basic conclusions unchanged, acknowledgements
adde
Dispersive approach to the axial anomaly and nonrenormalization theorem
Anomalous triangle graphs for the divergence of the axial-vector current are
studied using the dispersive approach generalized for the case of higher orders
of perturbation theory. The validity of this procedure is proved up to two-loop
level. By direct calculation in the framework of dispersive approach we have
obtained that the two-loop AVV amplitude is equal to zero. According to the
Vainshtein's theorem the transversal part of the anomalous triangle is not
renormalized in the chiral limit. We generalize this theorem for tha case of
finite fermion mass in the triangle loop.Comment: 12 pages, version to appear in Physical Review
Central exclusive production of scalar \chi_c meson at the Tevatron, RHIC and LHC energies
We calculate several differential distributions for exclusive double
diffractive production in proton-antiproton collisions at the
Tevatron and in proton-proton collisions at RHIC and LHC in terms of
unintegrated gluon distributions (UGDFs) within the -factorisation
approach. The uncertainties of the Khoze-Martin-Ryskin approach are discussed
in detail. The transition vertex is calculated as
a function of gluon virtualities applying the standard pNRQCD technique. The
off-shell effects are discussed and quantified. They lead to a reduction of the
cross section by a factor 2--5, depending on the position in the phase space
and UGDFs. Different models of UGDFs are used and the results are shown and
discussed. The cross section for diffractive component depends strongly on
UGDFs. We calculate also the differential distributions for the fusion mechanism. The integrated cross section for
photon-photon fusion is much smaller than that of diffractive origin. The two
components have very different dependence on momentum transfers in
the nucleon lines as well as azimuthal-angle correlations between both outgoing
nucleons.Comment: 34 pages, 23 figures, 2 table
Epidemiological manifestations of tuberculosis infection in the Omsk region: dynamics and trends
Background. Tuberculosis (TB) infection remains relevant as one of the leading public health problems in Russia.The aim. To characterize the dynamics and trends of epidemiological manifestations of TB infection in the Omsk region.Materials and methods. An observational descriptive-evaluative epidemiological study was carried out in the Omsk region from 2009 to 2021. The data available in the Federal statistical observation forms NN 7, 8, and 33, and results of the bacteriological study of patients with respiratory TB were analyzed.Results. In the Omsk region, an improvement in the epidemiological situation was observed from 2009 to 2021. It was associated with a decrease in TB prevalence by 3.7 times (from 325.6 to 86.7), mortality – by 5.8 times (from 21.1 to 3.6), incidence – by 2.7 times (from 130.7 to 48.4 per 100,000). At the same time, proportion of microscopy/culture-positive patients infected with multidrug-resistant Mycobacterium tuberculosis strains increased from 9.2 to 29.8 % among all patients, and from 15.5 to 30.6 % among newly diagnosed patients. There was a trend towards an increase in the number of cases with primary extensive drug resistance of M. tuberculosis. The incidence of tuberculosis associated with HIV infection has increased 10 times and reached 15.6 per 100,000 population.Conclusions. In the Omsk region, there is a change in the structure of M. tuberculosis strains with a predominance of multiple and extensive drug resistance along with decrease in TB incidence and mortality. New approaches are needed to organize the system of epidemiological surveillance and control of TB infection
Peculiarity of surgical rehabilitation of patients with head and neck tumors after radiotherapy
В роботі проведено дослідження медичної реабілітації у 42 пацієнтів після променевого лікування злоякісних новоутворень у ділянці голови і шиї. При необхідності можуть бути видалені зуби. При цьому хірургічні маніпуляції повинні бути максимально атравматичними і додатково для первинного загоювання може місцево застосовуватися гель «Апідент».In the paper, the observation of medical rehabilitation of 42 patients that occurred after radiation treatment of head and neck malignant tumors. Tooth removal is possible if necessary. Surgical technique should be as atraumatic as possible and in addition local gel “Apident” can be applied for primary wound closure
Dynamics and structure of mortality of patients with HIV infection in the Siberian federal district in 2006–2015
Objective: studying of dynamics, level, structure, features of territorial distribution of a mortality of patients with HIVinfection in the Siberian Federal District in 2015.Materials and methods: observation descriptive and estimated epidemiological research of these forms of federal statistical observation of subjects of the Siberian Federal District (SFD).Results: in the Siberian Federal district for the period of 2006–2015 dynamics of mortality of HIV-infected individuals was characterized by a high rate of growth (9,21%). For the entire period of study HIV infection in the region died 31772 patients, of whom 19,3 percent in 2015. The mortality rate of HIV-infected persons died from various causes in 2015 was 31.9 per 100 thousand population (6153). Male mortality is 2.6 times higher than the mortality of women (47,8 and 17,9 per 100 thousand population, respectively). More than 80% of persons died from HIV- infection were urban residents, 99,6 percent were over the age of 18 years. 43.9% of the deceased persons had the HIV-infection as a direct cause of death, they were under medical observation in 2015 (11,2 on 100 thousand population), of which 98.4% of the dead had late stage of HIV-infection. 47,4% of HIV-infected persons, who died from various causes, had coinfection of tuberculosis, mortality from tuberculosis in the later stages of HIVinfection was 12,9 per 100 thousand population. The distribution of mortality of HIV-infected persons in the territory of the Siberian Federal district was characterized by unevenness in the range from 1,3 in the Republic of Tuva to 52,2 in the Kemerovo region.Conclusion. The presence of a clear trend of increasing mortality of people living with HIV on the territory of the Siberian Federal district on the background of high prevalence of infection indicates the need of optimization of preventive measures and epidemiological surveillance system of HIV infection
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