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).
The scientifically based selection of efficient chemical technologies is related to the integrated assessment of indicators of their energy and resource efficiency and environmental safety, as well ...as indicators of the quality of products. The authors conducted systematic analysis of the efficiency and competitiveness of two electrochemical technologies of chroming from the solutions based on chromium salts of different valences. The strengths and weaknesses of each technology have been defined using the methodology of SWOT analysis, and the defined qualitative indicators of the efficiency of technologies have been determined using the methods of nonparametric statistics.
The development of digital technologies widely used in industry and agriculture sets strict requirements for sources of stabilized voltage across a range of parameters, each of which is important in ...its own way. However, a further increase in the resolution of analog-to-digital and digital-to-analog converters and, therefore, digital signal processing as a whole, is impossible without improving the voltage and current stabilizing coefficients, as well as the voltage temperature coefficient. This paper considers a method and a circuit design of a dc voltage stabilizer, the quality indicators of which—in particular, the input voltage stabilizing coefficient, the current stabilizing coefficient, and the voltage temperature coefficient—significantly exceed the typical ones.
A set of tectonophysical methods has been applied to reconstruct the neotectonic stresses of the southeastern Altai Mountains within the Chuya–Kurai depression and its framing structures. It is ...suggested that at the neotectonic stage, the tectonic structures of the Altai Mountains underwent a transformation of geodynamic conditions—a situation of sublatitudinal horizontal compression with predominant reverse-fault and transpressional movements along faults that existed up to the Neogene was replaced by horizontal shear conditions with a NNE and NE subhorizontal compression axis and WNW and NW extension axis. With such a stress field, the dominant NW-trending faults in this territory are mainly characterized by dextral strike-slip displacements, and NE-trending faults, by sinistral. Submeridionally trending faults that formed at the neotectonic stage show clear signs of extensional structures. A feature of the faults of the Chuya–Kurai depression according to these studies is a fairly small number of megafractures (indicators of shear displacements) in shear zones. This indicates dominant reverse-fault and transpressional movements over large disjunctive structures in the region in the Paleozoic and Mesozoic versus neotectonic shear movements. The results of the research are of practical importance in studying the regional seismicity.
A
bstract
The cross section of the process
e
+
e
−
→ ηπ
+
π
−
is measured using the data collected with the CMD-3 detector at the VEPP-2000 collider in the center-of-mass energy range from 1
.
1 to 2
....
0 GeV. The decay mode
η → γγ
is used for
η
meson reconstruction in the data sample corresponding to an integrated luminosity of 78
.
3 pb
−
1
. The energy dependence of the
e
+
e
−
→ ηπ
+
π
−
cross section is fitted within the framework of vector meson dominance in order to extract the Γ(
ρ
(1450)
→ e
+
e
−
)
B
(
ρ
(1450)
→ ηπ
+
π
−
) and the Γ(
ρ
(1700)
→ e
+
e
−
)
B
(
ρ
(1700)
→ ηπ
+
π
−
) products. Based on conservation of vector current, the analyzed data are used to test the relationship between the
e
+
e
−
→ ηπ
+
π
−
cross section and the spectral function in
τ
−
→ ηπ
−
π
0
ντ
decay. The
e
+
e
−
→ ηπ
+
π
−
cross section obtained with the CMD-3 detector is in good agreement with the previous measurements.
A
bstract
Model estimates are obtained for the influence of Coulomb effects on the ratio of the cross sections for the production of charged and neutral
B
$$ \overline{B} $$
B
¯
and
B
*
$$ ...\overline{B} $$
B
¯
*
pairs in
e
+
e
−
annihilation. It is shown that the difference between the masses of charged and neutral mesons obtained under the assumption that this ratio is constant on a scale of the order of the beam energy spread can differ from the true one by
δM
∼ 0
.
03 MeV at the energy of Υ(5
S
) and by
δM ∼
0
.
4 MeV at the energy of Υ(4
S
). Thus, the errors given in the PDG for the difference between the masses of charged and neutral
B
mesons, based on the results obtained at the energy of Υ(4
S
), are strongly underestimated. Similar measurements at the energy of Υ(5
S
) will have an order of magnitude smaller systematic shift for the mass difference. This circumstance should be taken into account when planning future experiments at the
B
factory in KEK.
Activity of ET Dra—a Star of FK Com Type Savanov, I. S.; Karpov, S. V.; Beskin, G. M. ...
Astrophysical bulletin,
12/2022, Letnik:
77, Številka:
4
Journal Article
Recenzirano
—We present new results of the study of ET Dra—a star of the FK Com type—based on observations carried out at the Zvenigorod Observatory of the Institute of Astronomy of RAS with the help of the ...FRAM-ORM telescope of the La Palma observatory (Spain) and the broadband optical monitoring system Mini-MegaTORTORA, located on the territory of the SAO RAS. We have studied changes in the shape of the light curve caused by the rotational modulation of a star with spots on its surface and the long-term variability of the star’s brightness. An independent determination of the rotation period of
was carried out using all sets of observations available to us. The increase in the brightness of the star near HJD 2459044 during observations with the FRAM-ORM telescope in all three filters was interpreted by us as a stellar flare. Our flare energy estimates are
,
, and
erg in the
,
, and
wavelength ranges, respectively. Observations with a duration of more than 2200 days, carried out at the SAO RAS, opened up the possibility of analyzing the long-term brightness variability of ET Dra. Evidence was found for the existence of cycles lasting 580 days and 810 days (1.55 and 2.23 years, respectively).
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