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.
The comparison of selected cases of polarization jet observation at ground stations and measurements of energetic ions at the AMPTE/CCE satellite shows that these phenomena occur simultaneously and ...on the same
L
shells. Polarization jet observations at DMSP satellites make it possible to statistically determine the dependence of its equatorial boundary position on the
AE
-index value. It is also shown that, in the case of isolated magnetic disturbances, the position of the inner boundary of injection of energetic ions measured at the AMPTE/CCE satellite depends on the
AE
index. It was found that the dependences of both boundaries on the
AE
index match over a wide range of
AE
variations. This is evidence that the equatorial boundary polarization jet band and the inner boundary of the injection of energetic ions are physically interconnected and are formed on the same
L
shells during substorms.
Abstract
In this paper, we propose a method that makes it possible to to improve energy reconstruction for data obtained via thin heterogeneous calorimeters for direct measurements of cosmic rays ...with energies of TeV and higher. Despite the large number of modern experimental complexes, the primary energy of cosmic nuclei with energies above 1 TeV is determined with large errors associated with fluctuations in the development of the cascade. For heterogeneous calorimeters, transient effects give an additional negative effect. In this paper we analyze the main causes of fluctuations and discuss a method for reducing the effect of fluctuations on the results of primary energy reconstruction. The method of accumulation of signal along the spectrum (ASAS) is used to reduce fluctuations associated with transient effects. The method was tested using the heterogeneous calorimeter of the PAMELA collaboration. It is shown that the proposed approach makes it possible to correctly determine the energy of slowly developing showers, the maxima of which are not measured.
Abstract
Mycelia of various
Armillaria
fungi are bioluminescent while the fruit bodies do not emit light. The presence in fruit bodies of
Armillaria
species of enzymes involved in the fungal ...bioluminescence was investigated by treating them with an exogenous analogue of the substrate for the light-emitting reaction. For this, hot extracts from nonluminous fungus
Pholiota squarrosa
were used. Upon spraying the pristine and transversely cut fruit bodies with the extracts, light emitting regions of different intensity were revealed. This suggests that the fruit bodies of the studied species are nonluminous due to lack of the substrate for light luminescent reaction. The prolonged incubation of the fruit bodies in water elevated the bioluminescence level. A possible mechanism which can explain this phenomenon is discussed.
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 electronic width of the
J
/
ψ
meson and its product by the branching fractions of
J
/
ψ
meson decay to hadrons and electrons measured with the KEDR detector at the VEPP-4M
e
+
e
−
collider have ...been reported in ref. 1.
Overview of the CMD-3 recent results Ryzhenenkov, A E; Akhmetshin, R R; Amirkhanov, A N ...
Journal of physics. Conference series,
04/2020, Letnik:
1526, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The CMD-3 detector started data taking at the electron-positron collider VEPP-2000 in December 2010 with a goal to collect about 1 fb−1. The collected data sample corresponds to an integrated ...luminosity of 200 pb−1 in the center-of-mass energy range from 0.32 up to 2 GeV. This paper reports recent results on the hadronic cross sections measurements with the CMD-3 detector.
We present a measurement of the pion form factor based on e+e− annihilation data from the CMD-2 detector in the energy range 0.6<s<1.0 GeV with a systematic uncertainty of 0.8%. A data sample is five ...times larger than that used in our previous measurement.
The development of digital technologies that are widely used in industry and farming imposes increased requirements on stabilized voltage sources for a whole number of parameters each of which is ...important in its own way. However, the resolution of analog-to-digital and digital-to-analog converters and, therefore, the entire procedure of digital signal processing cannot be further upgraded without improving such quality indicators of stabilized voltage sources as the stabilization coefficient and the noise level. This article considers a method and a circuit solution for constructing a low-noise source of stabilized dc voltage based on a general-purpose reference voltage source. The proposed solution reduces the output noise of a voltage stabilizer to a level slightly exceeding the natural noise of the best reference voltage source models while increasing the stability of the automatic control system (stability of the output voltage of the compensation stabilizer).
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