560 research outputs found
Properties of Neutral Charmed Mesons in Proton--Nucleus Interactions at 70 GeV
The results of treatment of data obtained in the SERP-E-184experiment
"Investigation of mechanisms of the production of charmed particles in
proton-nucleus interactions at 70 GeV and their decays" by irradiating the
active target of the SVD-2 facility consisting of carbon, silicon, and lead
plates, are presented. After separating a signal from the two-particle decay of
neutral charmed mesons and estimating the cross section for charm production at
a threshold energy {\sigma}(c\v{c})=7.1 \pm 2.4(stat.) \pm 1.4(syst.)
\mub/nucleon, some properties of D mesons are investigated. These include the
dependence of the cross section on the target mass number (its A dependence);
the behavior of the differential cross sections d{\sigma}/dpt2 and
d{\sigma}/dxF; and the dependence of the parameter {\alpha} on the kinematical
variables xF, pt2, and plab. The experimental results in question are compared
with predictions obtained on the basis of the FRITIOF7.02 code.Comment: 9 pages, 9 figures,3 table
Observation of narrow baryon resonance decaying into in pA-interactions at with SVD-2 setup
SVD-2 experiment data have been analyzed to search for an exotic baryon
state, the -baryon, in a decay mode at on IHEP
accelerator. The reaction with a limited multiplicity was
used in the analysis. The invariant mass spectrum shows a resonant
structure with and . The statistical significance of this peak was estimated to be of . The mass and width of the resonance is compatible with the recently
reported - baryon with positive strangeness which was predicted as an
exotic pentaquark () baryon state. The total cross section for
production in pN-interactions for was estimated to be
and no essential deviation from A-dependence for inelastic
events was found.Comment: 8 pages, 7 figures, To be submitted to Yadernaya Fizika. v3-v5 - Some
references added, minor typos correcte
Труднолечимый ревматоидный артрит. Какой он?
The widespread introduction into clinical practice of modern approaches to the treatment of rheumatoid arthritis (RA), the rational use of traditional and targeted antirheumatic drugs can effectively suppress inflammatory activity, restrain the progression of the disease and improve the quality of life of patients. At the same time, in some patients, even after the repeated change of targeted drugs, it is not possible to achieve the target level of RA activity. Serious difficulties arising in the management of such patients raised the question of identifying a special variant of the disease – difficult-to-treat (D2T) RA. The presence of various variants of D2T RA and the need to use a personalized approach to therapy justify the creation of special recommendations for the management of this category of patients. The first step in preparing these recommendations was the definition of D2T RA recently presented by the EULAR working group. It includes three criteria: 1) insufficient effectiveness of the therapy; 2) the presence of an active symptomatic disease; 3) clinical perception.Широкое внедрение в клиническую практику современных подходов к лечению ревматоидного артрита (РА), рациональное использование традиционных и таргетных противоревматических препаратов позволяют эффективно подавлять воспалительную активность, сдерживать прогрессирование болезни и улучшать качество жизни больных. Вместе с тем у части пациентов даже после повторной смены таргетных препаратов не удается добиться целевого уровня активности РА. Серьезные затруднения, возникающие при ведении таких пациентов, поставили вопрос о выделении особого варианта болезни – труднолечимого (difficult to treat, D2T) РА. Наличие разнообразных вариантов D2T РА и необходимость использования персонифицированного подхода к терапии обосновывают создание специальных рекомендаций по ведению данной категории больных. Первым шагом к подготовке данных рекомендаций стало определение понятия D2T РА, недавно представленное рабочей группой EULAR. Оно предусматривает соответствие пациента трем критериям: 1) недостаточная эффективность проводимой терапии; 2) наличие активного симптоматического заболевания; 3) клиническое восприятие
Charge Fluctuations in \pi^{+}\rp and \rK^{+}\rp Collisions at 250 GeV/
We report on measurements of event-by-event charge fluctuations in
\pi^{+}\rp and \rK^{+}\rp collisions at 250 GeV/. The dependence of
these fluctuations on the size of the rapidity windows are presented for the
first time in the full phase space domain. The corrections for the influence of
global charge conservation and leading-particle stopping are tested by the
data. The discrepancy due to incomplete correction given by STAR and PHENIX are
estimated. The dependence of the fluctuations on the position of the rapidity
bin and on the multiplicity at different rapidity windows are also presented.Comment: 4pages, 3figure
Rapidity, azimuthal, and multiplicity dependence of mean transverse momentum and transverse momentum correlations in and collisions in =22 GeV
Rapidity, azimuthal and multiplicity dependence of mean transverse momentum and transverse momentum correlations of charged particles is studied in pi/sup positive and K/sup positive collisions at 250 GeV/c incident beam momentum. For the first time, it is found that the rapidity dependence of the two-particle transverse momentum correlation is different from that of the mean transverse momentum, but both have similar multiplicity dependence. In particular, the transverse momentum correlations are boost invariant. This is similar to the recently found boost invariance of the charge balance function. A strong azimuthal dependence of the transverse momentum correlations originates from the constraint of energy-momentum conservation. The results are compared with those from the PYTHIA Monte Carlo generator. The similarities to and differences with the results from current heavy ion experiments are discussed
Combined QCD and electroweak analysis of HERA data
A simultaneous fit of parton distribution functions (PDFs) and electroweak
parameters to HERA data on deep inelastic scattering is presented. The input
data are the neutral current and charged current inclusive cross sections which
were previously used in the QCD analysis leading to the HERAPDF2.0 PDFs. In
addition, the polarisation of the electron beam was taken into account for the
ZEUS data recorded between 2004 and 2007. Results on the vector and
axial-vector couplings of the Z boson to u- and d-type quarks, on the value of
the electroweak mixing angle and the mass of the W boson are presented. The
values obtained for the electroweak parameters are in agreement with Standard
Model predictions.Comment: 32 pages, 10 figures, accepted by Phys. Rev. D. Small corrections
from proofing process and small change to Fig. 12 and Table
Limits on the effective quark radius from inclusive scattering at HERA
The high-precision HERA data allows searches up to TeV scales for Beyond the
Standard Model contributions to electron-quark scattering. Combined
measurements of the inclusive deep inelastic cross sections in neutral and
charged current scattering corresponding to a luminosity of around 1
fb have been used in this analysis. A new approach to the beyond the
Standard Model analysis of the inclusive data is presented; simultaneous
fits of parton distribution functions together with contributions of "new
physics" processes were performed. Results are presented considering a finite
radius of quarks within the quark form-factor model. The resulting 95% C.L.
upper limit on the effective quark radius is cm.Comment: 10 pages, 4 figures, accepted by Phys. Lett.
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