The general architecture and characteristics of the readout electronic system for the vertex detector of the SVD-2 setup at the U-70 accelerator (Kurchatov Institute NRC−IHEP, Protvino) are ...presented. The SVD-2 setup is intended to study near-threshold charmed-particle production at energies of 50–70 GeV, as well as many-particle processes and collective behavior of particles. The key characteristics of the electronic modules developed for the SVD setup by the Kurchatov Institute NRC−IHEP are briefly described.
The results of an analysis of data from the SERP-Е-184 experiment devoted to studying mechanisms of the production of charmed particles in proton–nucleus interactions at 70 GeV and their decays are ...presented. The data in question were obtained upon irradiating the SVD-2 active target consisting of carbon, silicon, and lead plates with a beam of 70-GeV protons. A detailed simulation on the basis of the FRITIOF7.02 and GEANT3.21 code packages made it possible to optimize event-selection criteria and to calculate the detection efficiency for Λ
c
+
baryons. After selecting a signal from the threebody decay of a Λ
c
+
baryon, the inclusive cross section for its production at near-threshold energies, its lifetime, and the parameter of the
A
dependence of the cross section were found. The Λ
c
+
-baryon yields are tabulated along with data from other experiments and theoretical predictions.
The stages of development and the current status of the versatile “Spectrometer with a Vertex Detector” setup designed for physics experiments at the U-70 accelerator of the Institute for High Energy ...Physics (Protvino) is described. The main detectors of the setup are the vertex detector based on silicon microstrip detectors, the wide-aperture magnetic spectrometer based on multiwire proportional chambers, and the lead-glass hodoscope γ detector. In the setup, there is a fast two-level trigger system for selecting required particle interactions. The key characteristics of the setup systems are presented, and the physical results obtained on it are briefly listed.
The results of E-190 experiment (project Thermalization) with 50 GeV proton beam irradiation of SVD-2 setup are presented. MC simulation has shown the linear dependence of number of photons detected ...in electromagnetic calorimeter and the average number of neutral pions. Multiplicity distribution of neutral pion, N0, for total number of particles in the event, Ntot = Nch + N0, are obtained with corrections on the setup acceptance, triggering and efficiency of the event reconstruction. The scaled variance of neutral pion fluctuations, ω = D/ < N0 >, versus total multiplicity is measured. The fluctuations increase at Ntot > 18. According to quantum statistics models this behavior can indicate a pion condensate formation in the high pion multiplicity system. This effect has been observed for the first time.
.
The results of the SERP-E-184 experiment at the U-70 accelerator (IHEP, Protvino) are presented. Interactions of the 70GeV proton beam with carbon, silicon and lead targets were studied to detect ...decays of charmed
D
0
,
D
¯
0
,
D
+
,
D
-
mesons and
Λ
c
+
baryon near their production threshold. Measurements of lifetimes and masses have shown a good agreement with PDG data. The inclusive cross-sections of charm production and their
A
-dependences have been obtained. The yields of these particles are compared with the theoretical predictions and the data of other experiments. The measured cross-section of the total open charm production (
σ
tot
(
c
c
¯
)
=
7
.
1
±
2
.
3
(
stat
)
±
1
.
4
(
syst
)
μb/nucleon) at the collision c.m. energy
√
s
=
11
.
8
GeV is well above the QCD model predictions. The contributions of different kinds of charmed particles to the total cross-section of the open charm production in proton-nucleus interactions vary with energy.
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