99 research outputs found
Measurement of decay rate and parameters at KEDR
Using the inclusive photon spectrum based on a data sample collected at the
peak with the KEDR detector at the VEPP-4M collider, we
measured the rate of the radiative decay as well
as mass and width. Taking into account an asymmetric photon
lineshape we obtained keV, MeV/, MeV.Comment: 6 pages, 3 figure
Measurement of J/psi to eta_c gamma at KEDR
We present a study of the inclusive photon spectra from 5.9 million J/psi
decays collected with the KEDR detector at the VEPP-4M e+e- collider. We
measure the branching fraction of radiative decay J/psi to eta_c gamma, eta_c
width and mass. Our preliminary results are: M(eta_c) = 2979.4+-1.5+-1.9 MeV,
G(eta_c) = 27.8+-5.1+-3.3 MeV, B(J/psi to eta_c gamma) = (2.34+-0.15+-0.40)%.Comment: To be published in Proceedings of the PhiPsi09, Oct. 13-16, 2009,
Beijing, Chin
Measurement of B(J/psi->eta_c gamma) at KEDR
We present a study of the inclusive photon spectrum from 6.3 million J/psi
decays collected with the KEDR detector at the VEPP-4M e+e- collider. We
measure the branching fraction of the radiative decay J/psi -> eta_c gamma,
eta_c width and mass. Taking into account an asymmetric photon line shape we
obtain: M(eta_c) = (2978.1 +- 1.4 +- 2.0) MeV/c^2, Gamma(eta_c) = (43.5 +- 5.4
+- 15.8) MeV, B(J/psi->eta_c gamma) = (2.59 +- 0.16 +- 0.31)%$.Comment: 6 pages, 1 figure. To be published in the proceedings of the 4th
International Workshop on Charm Physics (Charm2010), October 21-24, 2010,
IHEP, Beijin
Precise measurement of and between 1.84 and 3.72 GeV at the KEDR detector
The present work continues a series of the KEDR measurements of the value
that started in 2010 at the VEPP-4M collider. By combining new data
with our previous results in this energy range we measured the values of
and at nine center-of-mass energies between 3.08 and 3.72
GeV. The total accuracy is about or better than at most of energy
points with a systematic uncertainty of about . Together with the
previous precise measurement at KEDR in the energy range 1.84-3.05 GeV, it
constitutes the most detailed high-precision measurement near the
charmonium production threshold.Comment: arXiv admin note: text overlap with arXiv:1610.02827 and substantial
text overlap with arXiv:1510.0266
Status of the Super-B factory Design
The SuperB international team continues to optimize the design of an
electron-positron collider, which will allow the enhanced study of the origins
of flavor physics. The project combines the best features of a linear collider
(high single-collision luminosity) and a storage-ring collider (high repetition
rate), bringing together all accelerator physics aspects to make a very high
luminosity of 10 cm sec. This asymmetric-energy collider
with a polarized electron beam will produce hundreds of millions of B-mesons at
the (4S) resonance. The present design is based on extremely low
emittance beams colliding at a large Piwinski angle to allow very low
without the need for ultra short bunches. Use of crab-waist
sextupoles will enhance the luminosity, suppressing dangerous resonances and
allowing for a higher beam-beam parameter. The project has flexible beam
parameters, improved dynamic aperture, and spin-rotators in the Low Energy Ring
for longitudinal polarization of the electron beam at the Interaction Point.
Optimized for best colliding-beam performance, the facility may also provide
high-brightness photon beams for synchrotron radiation applications
EPIDEMIOLOGICAL AND EPIZOOTIOLOGICAL ANALYSIS OF THE SITUATION ON TULAREMIA IN THE RUSSIAN FEDERATION IN 2016 AND FORECAST FOR 2017
123 cases of human infection with Francisella tularensis were registered in the territory of the Russian Federation in 2016. 90 % of the total number was reported by three Federal Districts: North-Western, Siberian, and Central ones. Epizootic manifestations of varying intensity were detected in 56 regions. A considerable number of tularemia cases were observed in the Republic of Karelia, Nenets Autonomous District, Omsk and Ryazan Regions, and in Saint-Petersburg. Conspicuous are some recent peculiarities of tularemia manifestations: non-specificity of clinical symptoms, especially at early stages of the disease, their increasing variability against the background of mixed infections with tularemia and other natural-focal infections agents. The most expressed symptoms are fever and lymphatic adenitis; the patients are diagnosed with tularemia during initial days of the sought treatment in 40-45 % of the cases. Based on the data on morbidity rates in humans, epizootiological condition of natural tularemia foci, the numbers of isolated cultures and incidence of the vectors and carriers of the agent, as well as taking into consideration the scope of preventive vaccination in the regions, identified were the territories in which epidemic complication are most likely to occur in 2017
Measurement of with KEDR detector
The product of the electronic width of the meson and the branching
fractions of its decay to hadrons and electrons has been measured using the
KEDR detector at the VEPP-4M collider. The obtained values are:
The uncertainties shown are
statistical and systematic, respectively. Using the result presented and the
world-average value of the electronic branching fraction, one obtains the total
width of the meson: These
results are consistent with the previous experiments.Comment: 19 pages, 13 figure
Measurement of the ratio of the leptonic widths for the meson
The ratio of the electron and muon widths of the meson has been
measured using direct decays in the KEDR experiment at the VEPP-4M
electron-positron collider. The result
$\Gamma_{ee}(J/\psi)/\Gamma_{\mu\mu}(J/\psi)=1.0022\pm0.0044\pm0.0048\
(0.65\%)J/\psi$ lepton width
determination with up to 1% accuracy.Comment: 5 pages, 6 figures, 2 table
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