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.
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 an integrated luminosity of about 88 pb − 1 , of which 62 pb − 1 represent a complete dataset collected by CMD-3 at center-of-mass energies below 1 GeV. In the dominant region near the ρ resonance a systematic uncertainty of 0.7% was achieved. The implications of the presented results for the evaluation of the hadronic contribution to the anomalous magnetic moment of the muon are discussed. Published by the American Physical Society 2024
The paper describes a detector for carrying out diffraction experiments on a beam of synchrotron radiation, which is being developed at the Institute of Nuclear Physics of the Siberian Branch of the ...Russian Academy of Sciences. The detector will operate in the mode of direct counting of X-ray photons with an energy of more than 3–4 keV. A general description of the detector and its components is given, as well as a detailed description of the recording channel of an application-specific integrated circuit (ASIC). The results of the first measurements of the ASIC parameters are given and discussed in the article.
A
bstract
We present the study of the decay
J/ψ
→
ρπ
. The results are based on of 5.2 million
J/ψ
events collected by the KEDR detector at the VEPP-4M collider. The branching fractions are measured ...to be
B
(
J/ψ
→
ρπ
) = (2
.
072 ± 0
.
017 ± 0
.
062) ∙ 10
−
2
and
B
(
J/ψ
→
π
+
π
−
π
0
) = (1
.
878 ± 0
.
013 ± 0
.
051) ∙ 10
−
2
, where the first uncertainties are statistical and the second systematic. Our results are more precise than the previous relative measurements.
Using the 1.32
pb
-
1
statistics collected at the
J
/
ψ
peak with the KEDR detector at the VEPP-4M
e
+
e
-
collider, we measured the branching fractions of
J
/
ψ
meson decays to the final states 2(
π
...+
π
-
)
π
0
,
K
+
K
-
π
+
π
-
π
0
, 2(
π
+
π
-
)
and
K
+
K
-
π
+
π
-
. The results obtained for the decays
J
/
ψ
→
2(
π
+
π
-
)
π
0
,
J
/
ψ
→
K
+
K
-
π
+
π
-
π
0
contradict the measurements performed by other groups in the last century, but agree well with recent results of BABAR and BESIII collaborations.
The work describes a one-dimensional detector for diffraction experiments at a synchrotron radiation beam. The detector is being developed at the Budker Institute of Nuclear Physics, Siberian Branch, ...Russian Academy of Sciences. Until recently the institute was developing gas one-coordinate detectors, in particular a one-coordinate detector with calculated channels (OD-3M), based on the technology of multiwire proportional chambers. To provide a spatial resolution better than 100 microns at a photon energy in a wide energy range (3–30 keV), it is necessary to use solid-state microstrip or matrix sensors in combination with specialized integrated registration circuits. The developed SOCOD detector, using a microstrip sensor based on gallium arsenide as a registration element, operates in the mode of the direct counting of photons with an energy of more than 3–4 keV and a speed of up to 1 MHz/channel. The work gives a general description of the current version of the detector, a block diagram of the registration channel, the software allowing users to control the operation of the detector and display the results obtained, and the developed algorithm for leveling the trigger thresholds in the channels. The results of electronic tests, the work of the alignment algorithm and their discussion are presented.
In this paper, we describe the current state of development of a prototype detector for the study of fast processes (DIMEX) based on a silicon microstrip sensor. The silicon microstrip sensor is made ...of
n
-type silicon with
p
-type implants in the form of strips. Aluminum contacts with microwelding pads at the ends are applied to the strips along the entire length. The signals from the strips are read using a DMXS6A integrated circuit specially designed for this project, which contains six recording electronic channels with a dark-current compensation circuit at the input, four integrators, 32 analog memory cells, and an analog shift register. Each sensor strip is connected to the guard ring through a 400-Ω resistor and to the recording-channel input through a 100-kΩ resistor. This resistive divider at the input of the recording channel makes it possible to adapt the dynamic range of the recording microcircuit integrator to the full range of photon-flux changes in synchrotron-radiation output channel no. 8 of the VEPP-4M storage ring equipped with a nine-pole wiggler with a field of 1.95 T as the source of synchrotron radiation. Measurements of the dynamic range of the DIMEX-Si prototype show that the maximal flux that can be recorded in the linear mode exceeds 10
5
photons/channel from each electron bunch in the storage ring. The ability of the detector to detect signals from bunches following after 55 ns in the multi-bunch mode, which simulates the operation of the 4+-generation synchrotron-radiation source Siberian Circular Photon Source (SKIF) under construction in the Novosibirsk region, on which such a detector is planned to be used, is also demonstrated.
Measurement of Γee(J/ψ) with KEDR detector Anashin, V. V; Aulchenko, V. M; Baldin, E. M ...
The journal of high energy physics,
05/2018, Volume:
2018, Issue:
5
Journal Article
Peer reviewed
Open access
A
bstract
The product of the electronic width of the
J/ψ
meson and the branching fractions of its decay to hadrons and electrons has been measured using the KEDR detector at the VEPP-4M
e
+
e
−
...collider. The obtained values are
Γ
e
e
J
/
ψ
=
5.550
±
0.056
±
0.089
keV
,
Γ
e
e
J
/
ψ
·
ℬ
hadrons
J
/
ψ
=
4.884
±
0.048
±
0.078
keV
,
Γ
e
e
J
/
ψ
·
ℬ
e
e
J
/
ψ
=
0.3331
±
0.0066
±
0.0040
keV
.
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
J/ψ
meson:
Γ
=
92.94
±
1.83
keV
.
These results are consistent with the previous experiments.
This paper describes systematic measurements of the main parameters of the DIMEX-Si silicon microstrip detector prototype, designed to study fast processes in a beam of synchrotron radiation (SR). ...The dynamic range, spatial resolution and temporal parameters of the detector are estimated. The parameters of the prototype silicon detector are compared with the DIMEX-G gas version. The maximum flux which can be measured by the silicon detector is 40 times higher than that of the gas detector. The spatial resolution of the silicon detector is 130 microns and that of the gas detector is 250 microns. The estimated time resolution of the silicon detector is 15 ns, while for a gas detector this value is about 50 ns. All the characteristics of DIMEX-Si are measured with a cycle time of 25 ns. The results of the first tests of a full-scale silicon detector for diffraction studies, operating in the integrating mode at a speed of up to 2 Mframes/s, are also given. The sensor contains 1024 strips 30 mm long with a step of 50 microns; 512 of these strips are connected to readout electronics based on APC128 ASIC. Each chip contains 128 channels, which consist of a low-noise integrator with 32 analog memory cells. The possibility of signal visualization from single photons and electrons from
109
Cd and
90
Sr sources is shown.
PDF
