2,422 research outputs found
Special features of the Be2He fragmentation in emulsion at an energy of 1.2~A~GeV
The results of investigations of the relativistic Be nucleus
fragmentation in emulsion which entails the production of two He fragments of
an energy of 1.2~A~GeV are presented. The results of the angular measurements
of the Be2He events are analyzed.
The BeBe+n fragmentation channel involving the Be decay from
the ground (0) and the first excited (2) states to two
particles is observed to be predominant.Comment: 10 pages, 6 figures, conference: Conference on Physics of Fundamental
Interactions, Moscow, Russia, 5-9 Dec 2005 (Author's translation
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
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
Anthropometric and functional characteristics of athletes involved in combat sports in the Greco-Roman style
Objective: to determine the morphological and functional parameters of athletes-junior wrestlers, determining their specialization, qualification and training in ontogenesis. Materials and methods: 49 male junior athletes of the school of Olympic reserve engaged in martial arts in the GrecoRoman style for 6-10 years were examined. We used the Dorokhov R.N. (1994) technique of selection and early orientation in sports to determine the anthropometric temporal characteristics. Following functional indicators were determined: absolute and relative physical performance, aerobic performance, power index eagerly, type of vegetative regulation. Results: the majority of fighters teenagers CMS had mesosomal, microcorpulent, micromesomelic, micromesic and mesomacromembral somatotype. A comprehensive study of the functional parameters of the wrestlers showed that indicators of absolute and relative physical performance were higher in young men CMS and were respectively 1318.6±149.5 kg∙m/min and 19.3±2.5 kg∙m/(min∙kg). Aerobic performance was higher in adolescents and first-rank sportsmen: 51.8±9.36 ml/(min∙kg). The strength indices of the hands were higher in the young men's CMS and contributed to 70.6±6.37% for the right hand and 66.08±12.1% for the left hand, which was explained by the component body composition of the body of young men. Most of the wrestlers revealed moderate parasympathicotonia and amphotonic. Conclusions: the R.N. Dorokhova and V.G. Petrukhina (1994) method of somatotyping allows to differentiate athletes, involved in martial arts in the Greco-Roman style, into 3 levels of variation: dimensional, component and proportion and to determine their specialization, qualification and degree of training in ontogenesis
Fragmentation of relativistic nuclei in peripheral interactions in nuclear track emulsion
The technique of nuclear track emulsions is used to explore the fragmentation
of light relativistic nuclei down to the most peripheral interactions - nuclear
"white" stars. A complete pattern of therelativistic dissociation of a B
nucleus with target fragment accompaniment is presented. Relativistic
dissociation Be is explored using significant statistics and
a relative contribution of Be decays from 0 and 2 states is
established. Target fragment accompaniments are shown for relativistic
fragmentation N3He+H and Ne5He. The leading role of the
electromagnetic dissociation on heavy nuclei with respect to break-ups on
target protons is demonstrated in all these cases. It is possible to conclude
that the peripheral dissociation of relativistic nuclei in nuclear track
emulsion is a unique tool to study many-body systems composed of lightest
nuclei and nucleons in the energy scale relevant for nuclear astrophysics.Comment: 15 pages, 4 figures, 4 tables, conference: Relativistic nuclear
physics: from Nuclotron to LHC energies, Kiev, June 18-22, 200
Investigation of Light Nucleus Clustering in Relativistic Multifragmentation Processes
The use of emulsions for studying nuclear clustering in light nucleus
fragmentation processes at energies higher than 1A GeV is discussed. New
results on the topologies of relativistic Li-7 and B-10 nucleus fragmentation
in peripheral interactions are given. A program of research of the cluster
structure in stable and radioactive nuclei is suggested.Comment: 4 pages, 1 figure. Presented at Conference on Fundamental
Interactions, 2-6 December 2002, ITEP, Moscow, Russia (misprints are removed
Horn fragments of the Halpern-Shoham Interval Temporal Logic
We investigate the satisfiability problem for Horn fragments of the Halpern-Shoham interval temporal logic depending on the type (box or diamond) of the interval modal operators, the type of the underlying linear order (discrete or dense), and the type of semantics for the interval relations (reflexive or irreflexive). For example, we show that satisfiability of Horn formulas with diamonds is undecidable for any type of linear orders and semantics. On the contrary, satisfiability of Horn formulas with boxes is tractable over both discrete and dense orders under the reflexive semantics and over dense orders under the irreflexive semantics but becomes undecidable over discrete orders under the irreflexive semantics. Satisfiability of binary Horn formulas with both boxes and diamonds is always undecidable under the irreflexive semantics
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