1,000 research outputs found
Characteristics of alpha projectile fragments emission in interaction of nuclei with emulsion
The properties of the relativistic alpha fragments produced in interactions
of 84^Kr at around 1 A GeV in nuclear emulsion are investigated. The
experimental results are compared with the similar results obtained from
various projectiles with emulsion interactions at different energies. The
total, partial nuclear cross-sections and production rates of alpha
fragmentation channels in relativistic nucleus-nucleus collisions and their
dependence on the mass number and initial energy of the incident projectile
nucleus are investigated. The yields of multiple alpha fragments emitted from
the interactions of projectile nuclei with the nuclei of light, medium and
heavy target groups of emulsion-detector are discussed and they indicate that
the projectile-breakup mechanism seems to be free from the target mass number.
It is found that the multiplicity distributions of alpha fragments are well
described by the Koba-Nielsen-Olesen (KNO) scaling presentation. The mean
multiplicities of the freshly produced newly created charged secondary
particles, normally known as shower and secondary particles associated with
target in the events where the emission of alpha fragments were accompanied by
heavy projectile fragments having Z value larger than 4 seem to be constant as
the alpha fragments multiplicity increases, and exhibit a behavior independent
of the alpha fragments multiplicity.Comment: 33 pages, 8 figures and 3 tables (in press
Topology of "white" stars in relativistic fragmentation of light nuclei
In the present paper, experimental observations of the multifragmentation
processes of light relativistic nuclei carried out by means of emulsions are
reviewed. Events of the type of "white" stars in which the dissociation of
relativistic nuclei is not accompanied by the production of mesons and the
target-nucleus fragments are considered.
A distinctive feature of the charge topology in the dissociation of the Ne,
Mg, Si, and S nuclei is an almost total suppression of the binary splitting of
nuclei to fragments with charges higher than 2. The growth of the nuclear
fragmentation degree is revealed in an increase in the multiplicity of singly
and doubly charged fragments with decreasing charge of the non-excited part of
the fragmenting nucleus.
The processes of dissociation of stable Li, Be, B, C, N, and O isotopes to
charged fragments were used to study special features of the formation of
systems consisting of the lightest , d, and t nuclei. Clustering in
form of the He nucleus can be detected in "white" stars via the
dissociation of neutron-deficient Be, B, C, and N isotopes.Comment: 20 pages, 3 figures, 9 tables, conference: Conference on Physics of
Fundamental Interactions, Moscow, Russia, 1-5 Mar 2004.(Author's translation
Clustering in light nuclei in fragmentation above 1 A GeV
The relativistic invariant approach is applied to analyzing the 3.3 A GeV
Ne fragmentation in a nuclear track emulsion. New results on few-body
dissociations have been obtained from the emulsion exposures to 2.1 A GeV
N and 1.2 A GeV Be nuclei. It can be asserted that the use of the
invariant approach is an effective means of obtaining conclusions about the
behavior of systems involving a few He nuclei at a relative energy close to 1
MeV per nucleon. The first observations of fragmentation of 1.2 A GeV B
and C nuclei in emulsion are described. The presented results allow one
to justify the development of few-body aspects of nuclear astrophysics.Comment: 7 pages, 8 figures, 3 tables, Nuclear Physics in Astrophysics-2,
16-20 May, 2005 (ATOMKI), Debrecen, Hungar
Production asymmetry of D mesons in collisions
We study the production asymmetry of charm versus anticharm mesons in
photon-proton interactions. We consider photon gluon fusion plus higher order
corrections in which light quarks through vector meson-proton interactions
contribute to the cross section. Non perturbative effects are included in terms
of a recombination mechanism which gives rise to a production asymmetry.Comment: 15 pages, including 5 postscript figures. LaTeX. To appear in Phys.
Lett.
Charge electric vehicles
Many enterprises in Russia are currently engaged in the development of temperature and humidity regulators. It happens due to the fact that in every small town and even village there are manufacturers using technological processes associated with the regulation of these parameters. The article analyzes the control and measuring devices for controlling the temperature regime of the cooking cabinet. The devices of the "Thermodat" series produced by LLC "UralTeploPribor" and "MPR 51" of the company "Aries"are considered. The advantages and disadvantages of the devices are revealed. The analysis of the application of the control device for the temperature and humidity regime of the cooking cabinet is carried out
Enabling comparison of UrQMD with Geant4 hadronic models
Geant4 has an abundant set of physics models that handle the diverse
interaction of particles with matter across a wide energy range. However, there
are also many well established reaction codes currently used in the same fields
where Geant4 is applied. One such code is the Ultra-relativistic Quantum
Molecular Dynamics (UrQMD) model. In order to take advantage of the UrQMD code,
we create a tool to enable comparisons among UrQMD and Geant4 hadronic models.
This tool allows a user to process the output file of UrQMD through Geant4
toolkit, while at the same time, can choose among different Geant4 hadronic
model generators. As an example, the UrQMD model is compared with the HARP-CDP
experimental data and with the Binary and FRITIOF generators, in the framework
of Geant4. It is shown that the UrQMD model can better reproduce charged pion
production for p+Cu and Pb interactions at 3, 8 and 15 GeV/c, and is a good
candidate for Geant4 hadronic models.Comment: 17 pages, 5 Figure
The high-intensity hyperon beam at CERN
A high-intensity hyperon beam was constructed at CERN to deliver Sigma- to
experiment WA89 at the Omega facility and operated from 1989 to 1994. The setup
allowed rapid changeover between hyperon and conventional hadron beam
configurations. The beam provided a Sigma-flux of 1.4 x 10^5 per burst at mean
momenta between 330 and 345 Gev/c, produced by about 3 x 10^10 protons of 450
GeV/c . At the experiment target the beam had a Sigma-/pi- ratio close to 0.4
and a size of 1.6 x 3.7 cm^2. The beam particle trajectories and their momenta
were measured with a scintillating fibre hodoscope in the beam channel and a
silicon microstrip detector at the exit of the channel. A fast transition
radiation detector was used to identify the pion component of the beam.Comment: 20 pages, 13 figures. Submitted to Nucl. Instr. Meth.
Charge electric vehicles
Many enterprises in Russia are currently engaged in the development of temperature and humidity regulators. It happens due to the fact that in every small town and even village there are manufacturers using technological processes associated with the regulation of these parameters. The article analyzes the control and measuring devices for controlling the temperature regime of the cooking cabinet. The devices of the "Thermodat" series produced by LLC "UralTeploPribor" and "MPR 51" of the company "Aries"are considered. The advantages and disadvantages of the devices are revealed. The analysis of the application of the control device for the temperature and humidity regime of the cooking cabinet is carried out
Fragmentation channels of relativistic Be nuclei in peripheral interactions
Nuclei of Li were accelerated at the JINR Nuclotron. After the
charge-exchange reaction involving these nuclei at an external target a second
Be beam of energy 1.23A GeV was formed. This beam was used to expose
photo-emulsion chambers. The mean free path for inelastic Be interactions
in emulsion =14.00.8 cm coincides within the errors with those
for Li and Li nuclei. More than 10% of the Be events are associated
with the peripheral interactions in which the total charge of the relativistic
fragments is equal to the charge of the Be and in which charged mesons are
not produced. An unusual ratio of the isotopes is revealed in the composition
of the doubly charged Be fragments: the number of He fragments is twice
as large as that of He fragments. In 50% of peripheral interactions, a
Be nucleus decays to two doubly charged fragments. The present paper gives
the channels of the Be fragmentation to charged fragments. In 50% of
events, the Be fragmentation proceeds only to charged fragments involving
no emission of neutrons. Of them, the He+He channel dominates, the
He+d+p and Li+pchannels constitute 10% each. Two events involving no
emission of neutrons are registered in the 3-body He+t+p and He+d+d
channels. The mean free path for the coherent dissociation of relativistic
Be nuclei to He+He is 71 m. The particular features of the
relativistic Be fragmentation in such peripheral interactions are explained
by the He+He 2-cluster structure of the Be nucleus.Comment: 10 pages, 3 figures, 3 tables, conference: Conference on Physics of
Fundamental Interactions, Moscow, Russia, 5-9 Dec 200
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