Searches for the process of electron–positron (
) annihilation to the
(2007)
meson were performed by means of the CMD-3 detector at the VEPP-2000
collider. In the data analysis, use was made of two ...dominant modes of
-meson decay to
and
, where
was reconstructed in the
channel. By employing a 3.7 pb
data sample accumulated at the c.m. energy of
MeV, an upper bound of
on the decay branching ratio was obtained at a
confidence level.
A preliminary result of an analysis of the process
whose cross section was measured in the range of center-of-mass collision energies between 1.2 and 2 GeV is presented. The analysis is based on the ...data sample corresponding to an integrated luminosity of about 120 pb
accumulated with the CMD-3 detector at the VEPP-2000 electron–positron collider. A procedure for separating signal events is developed, and the dominance of the
neutral mode is confirmed. The cross section for the process
is measured to a precision higher than that in earlier experiments. This permits improving the accuracy in measuring the mass and width of the
(1680) meson, testing the accuracy of the isotopic relations, and more accurately calculating the hadronic contribution to the muon anomalous magnetic moment (
).
The cross section of the process e + e − → π + π − has been measured in the center of mass energy range from 0.32 to 1.2 GeV with the CMD-3 detector at the electron-positron collider VEPP-2000. The ...measurement is based on a full dataset collected below 1 GeV during three data taking seasons, corresponding to an integrated luminosity of about 62 pb − 1 . In the dominant ρ -resonance region, a systematic uncertainty of 0.7% has been reached. At energies around ϕ -resonance the π + π − production cross section was measured for the first time with high beam energy resolution. The forward-backward charge asymmetry in the π + π − production has also been measured. It shows a strong deviation from the theoretical prediction based on the conventional scalar quantum electrodynamics framework, and it is in good agreement with the generalized vector-meson-dominance and dispersive-based predictions. The impact of the presented results on the evaluation of the hadronic contribution to the anomalous magnetic moment of muon is discussed. Published by the American Physical Society 2024
The aim
of the work was to determine the effective ultraviolet (UV) doses required for the disinfection of surfaces contaminated with the SARS-CoV-2 coronavirus using a low-pressure mercury lamp.
...Materials and methods
. To carry out prompt disinfection of surfaces, a specially designed source of UV radiation with a power of 7.5 W at a wavelength of 254 nm in the form of a portable flashlight was employed, which has a high efficiency of UV radiation output and the possibility of long-term autonomous operation from a compact battery. In the studies, a suspension culture of the SARS-CoV-2 coronavirus with biological activity of 5.3∙10
6
PFU/ml was used. The objects of testing were plastic Petri dishes (disposable) and office paper (grade C, density 80 g/m
2
).
Results and discussion
. Doses of UV radiation that provide disinfection of surfaces contaminated with the COVID-19 pathogen with an efficiency of 99.0 % (paper) to 99.95 % (plastic) have been determined. The results obtained make it possible to recommend a portable UV irradiator for use in the practice of preventive measures to combat the spread of the disease caused by the SARS-CoV-2 coronavirus.
The time-of-flight (TOF) system now is installed at the CMD-3 detector of the VEPP-2000 electron-positron collider at the Budker Institute of Nuclear Physics. It is based on the strips of organic ...scintillator with shifter fibers readout and silicon photomultiplier (SiPM) photodetectors. The new electronics for TOF system is designed at the Budker Institute of Nuclear Physics. The main feature of the new electronics is usage a ripple-free technology for providing a bias voltage for SiPM photodetectors. Also this design has very low power consumption. It allows the individual controlled bias voltage generator to be integrated to front-end electronics, near the photodetectors. In this paper the structure of the TOF electronic hardware is described.
Barrel calorimeter of the CMD-3 detector Anisenkov, A.V.; Aulchenko, V.M.; Barkov, L.M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2013, Letnik:
732
Journal Article
Recenzirano
Since 2010 the CMD-3 detector has been collecting data at the e+e− collider VEPP-2000 at Budker Institute of Nuclear Physics. CMD-3 is a general purpose detector designed to study e+e− annihilation ...into hadrons in the wide energy range s=0.3–2GeV. The CMD-3 barrel electromagnetic calorimeter consists of two subsystems: closest to the beam pipe is the Liquid Xenon calorimeter and the outer one is based on CsI scintillation crystals. The design of the calorimeter and its current performance are presented.
The paper describes a method of the charged particle identification, developed for the CMD-3 detector, installed at the VEPP-2000 e+e− collider. The method is based on application of boosted decision ...trees classifiers, trained for the optimal separation of electrons, muons, pions and kaons in the momentum range from 100 to 1200MeV/c. The input variables for the classifiers are linear combinations of the energy depositions of charged particles in 12 layers of the liquid xenon calorimeter of the CMD-3. The event samples for training of the classifiers are taken from the simulation. Various issues of the calorimeter strip channels response simulation and their calibration are considered. Application of the method is illustrated by the examples of separation of the e+e−(γ) and π+π−(γ) final states and of selection of the K+K− final state at high energies.
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