127 research outputs found
Feynman scaling violation on baryon spectra in pp collisions at LHC and cosmic ray energies
A significant asymmetry in baryon/antibaryon yields in the central region of
high energy collisions is observed when the initial state has non-zero baryon
charge. This asymmetry is connected with the possibility of baryon charge
diffusion in rapidity space. Such a diffusion should decrease the baryon charge
in the fragmentation region and translate into the corresponding decrease of
the multiplicity of leading baryons. As a result, a new mechanism for Feynman
scaling violation in the fragmentation region is obtained. Another numerically
more significant reason for the Feynman scaling violation comes from the fact
that the average number of cutted Pomerons increases with initial energy. We
present the quantitative predictions of the Quark-Gluon String Model (QGSM) for
the Feynman scaling violation at LHC energies and at even higher energies that
can be important for cosmic ray physics.Comment: 21 pages, 11 figures, and 1 table. arXiv admin note: substantial text
overlap with arXiv:1107.1615, arXiv:1007.320
Quark-Gluon String Model Description of Baryon Production in K^{\pm}N Interactions
The process of baryon production in K p collisions at high energies is
considered in the framework of the Quark-Gluon String Model. The contribution
of the string-junction mechanism to the strange baryon production is analysed.
The results of numerical calculations are in reasonable agreement with the data
on inclusive spectra of p, Lambda, bar{Lambda}, and on the bar{Lambda}/Lambda
asymmetry. The predictions for Xi and Omega baryons are presented.Comment: 19 pages, 7 figure
The Updated Zwicky Catalog (UZC)
The Zwicky Catalog of galaxies (ZC), with m_Zw<=15.5mag, has been the basis
for the Center for Astrophysics (CfA) redshift surveys. To date, analyses of
the ZC and redshift surveys based on it have relied on heterogeneous sets of
galaxy coordinates and redshifts. Here we correct some of the inadequacies of
previous catalogs by providing: (1) coordinates with <~2 arcsec errors for all
of the Nuzc catalog galaxies, (2) homogeneously estimated redshifts for the
majority (98%) of the data taken at the CfA (14,632 spectra), and (3) an
estimate of the remaining "blunder" rate for both the CfA redshifts and for
those compiled from the literature. For the reanalyzed CfA data we include a
calibrated, uniformly determined error and an indication of the presence of
emission lines in each spectrum. We provide redshifts for 7,257 galaxies in the
CfA2 redshift survey not previously published; for another 5,625 CfA redshifts
we list the remeasured or uniformly re-reduced value. Among our new
measurements, Nmul are members of UZC "multiplets" associated with the original
Zwicky catalog position in the coordinate range where the catalog is 98%
complete. These multiplets provide new candidates for examination of tidal
interactions among galaxies. All of the new redshifts correspond to UZC
galaxies with properties recorded in the CfA redshift compilation known as
ZCAT. About 1,000 of our new measurements were motivated either by inadequate
signal-to-noise in the original spectrum or by an ambiguous identification of
the galaxy associated with a ZCAT redshift. The redshift catalog we include
here is ~96% complete to m_Zw<=15.5, and ~98% complete (12,925 galaxies out of
a total of 13,150) for the RA(1950) ranges [20h--4h] and [8h--17h] and
DEC(1950) range [-2.5d--50d]. (abridged)Comment: 34 pp, 7 figs, PASP 1999, 111, 43
Pion Content of the Nucleon as seen in the NA51 Drell-Yan experiment
In a recent CERN Drell-Yan experiment the NA51 group found a strong asymmetry
of and densities in the proton at . We interpret
this result as a decisive confirmation of the pion-induced sea in the nucleon.Comment: 10 pages + 3 figures, Preprint KFA-IKP(TH)-1994-14 .tex file. After
\enddocument a uu-encodeded Postscript file comprising the figures is
appende
Lambda-Baryon Production in pi(+-)n Interactions
The process of Lambda-baryon production in pi-p collisions is considered. The
contribution of the string-junction mechanism to the strange baryon production
in meson-baryon scattering is anlysed. The results of numerical calculations in
the framework of the Quark-Gluon String model are in reasonable agreement with
the data.Comment: 10 pages and 5 figue
A Complete Redshift Survey to the Zwicky Catalog Limit in a 2-hour by 15-degree Region Around 3C 273
We compile 1113 redshifts (648 new measurements, 465 from the literature) for
Zwicky catalogue galaxies in the region (-3.5deg < \delta < 8.5deg, 11.5h <
\alpha < 13.5h). We include redshifts for 114 component objects in 78 Zwicky
catalogue multiplets. The redshift survey in this region is 99.5% complete to
the Zwicky catalogue limit, m_Zw=15.7. It is 99.9% complete to m_Zw = 15.5, the
CfA Redshift Survey (CfA2) magnitude limit.
The survey region is adjacent to the northern portion of CfA2, overlaps the
northernmost slice of the Las Campanas Redshift Survey, includes the southern
extent of the Virgo Cluster, and is roughly centered on the QSO 3C 273. As in
other portions of the Zwicky catalogue, bright and faint galaxies trace the
same large-scale structure.Comment: 43 pages (3 tables and 4 figures included separately); ApJS, in pres
Моделирование процессов возникновения и роста фрактальных структур и дефектов камер теплоэнергетических установок. Часть 1
The paper considers modeling the emergence and growth of possible fractal structures and defects on the inner surface of the chambers of thermal power units, which allow control and regulation of the development of such stochastic dynamic processes. We are talking about the use of modeling procedures for the given analysis, which are quite universal in the framework of certain approaches. A general qualitative consideration of the modeling of processes such as the deposition of materials on a solid surface of various complex configurations, and the occurrence of its fracturing and defects of fractal types, is given. In the first part, we consider an analogy between the processes of the emergence and growth of fractal structures and chamber defects with laser processes of controlled deposition of substances on the surface of a solid body and the growth of its fracturing. A number of models have been developed for the emergence and growth of fractal inhomogeneities of various types and configurations on a solid surface with identification of the possibility of their preliminary monitoring at the initial stage of their appearance. At the same time, both various surfaces in the form of coatings and the formation of fracturing and cluster zones of inhomogeneities and defects have been analyzed. The emphasis in the course of research has been made both on the analysis of their regulated structure, and also on the dynamics of the growth of fracturing and cluster zones of heterogeneities and defects in a certain direction. At the initial stage, the indicated process of formation of fractures and cluster zones of inhomogeneities and defects in space was monitored with different scaling: nano- and microscales. This study has been carried out within the framework of an analogy under the following conditions: firstly, given control over the cha-racteristics of similar objects in the corresponding laser experiment; secondly, the presence of a real possibility of ensuring their formation on the inner surfaces of the chambers in contact with the working substance; thirdly, the possibility of such structures influencing on the efficiency of various types of thermal power units in the context of achieving the desired direction and/or undesirability of changing the indicators and characteristics of units taking into account the laws of technical thermodynamics.Рассматривается моделирование возникновения и роста возможных фрактальных структур и дефектов на внутренней поверхности камер тепловых энергетических установок, допускающих контролирование и регулирование развития таких стохастических динамических процессов. Речь идет об использовании процедур моделирования для приводимого анализа, имеющих достаточно универсальный характер в рамках определенных подходов. Приведено общее качественное рассмотрение моделирования процессов как осаждения материалов на твердую поверхность различных сложных конфигураций, так и возникновения ее трещиноватости и дефектов фрактальных типов. В первой части проводится аналогия процессов возникновения и роста фрактальных структур и дефектов камер с лазерными процессами управляемого осаждения веществ на поверхность твердого тела и роста ее трещиноватости. Развит ряд моделей возникновения и роста фрактальных неоднородностей разного типа и конфигураций на твердой поверхности с выявлением возможности их предварительного мониторинга на начальном этапе появления. При этом проанализированы как различные поверхности в виде покрытий, так и образование трещиноватости и кластерных зон неоднородностей и дефектов. Акцент в ходе исследований сделан на анализе регулируемой их структуры, а также на динамике роста трещиноватости и кластерных зон неоднородностей и дефектов в определенном направлении. На начальном этапе осуществлялся мониторинг указанного процесса образования в пространстве трещиноватости и кластерных зон неоднородностей и дефектов с различным масштабированием: нано- и микромасштабами. Данное исследование проведено в рамках аналогии в условиях: во-первых, заданного управления характеристиками подобных объектов в соответствующем лазерном эксперименте; во-вторых, наличия реальной возможности обеспечения их образования на внутренних поверхностях камер при контакте с рабочим веществом; в-третьих, возможности влияния таких структур на эффективность работы тепловых энергетических установок разного типа в контексте достижения нужной направленности и/или нежелательности изменения показателей и характеристик установок с учетом закономерностей технической термодинамики
Моделирование процессов возникновения и роста фрактальных структур и дефектов камер теплоэнергетических установок. Часть 2
The paper describes further development of model studies with the purpose to draw analogies of the occurrence of possible inhomogeneities and defects of the fractal type on the surface of various objects under the action of laser radiation for different conditions and schemes of a laser simulation experiment in comparison with real processes in the chambers of thermal machines due to the contacts of the working substances with their surface. The subject of this consideration is related to the fact that in laser schemes one can relatively easily and in a controlled manner to study their topology in various modifications (in the range of 0D–3D structures formed on surfaces of various geometric shapes of the fractal type). This provides great opportunities for studying various frequently occurring undesirable random defects and inhomogeneities of complex configuration with the development of unexpected processes in the dynamic modes of operation of various types of power units in their actual operation. This is determined by geometric analysis within the framework of the correspondding non-linear models with different non-linear fractal images. In this aspect, we have used two models to consider the development of emerging fractal fractured structures: first, diffusion propagation/growth of cracks of different geometry with a set of local segments and fragments in different directions; secondly, with diffusely limited aggregation of their distribution (Diffusion-Limited Aggregation – DLA) using the formalism of cellular automata in percolation approximation for different algorithms for the formation of fractal structures. We present only the final results of calculations without details of their procedure, which is sufficient for a visual and qualitative determination of the process of growth of fracturing and defects. In this case, the final goal of consideration is to study the emergence of possible and controllable local areas / collectors, starting from surface structures, and their association with real objects on the surface of chambers with a working substance in power systems. The possible practical significance of such modeling and analysis is discussed to forecast their working conditions.В данной статье находят дальнейшее развитие модельные исследования по проведению аналогий возникновения возможных неоднородностей и дефектов фрактального типа на поверхности различных объектов под действием лазерного излучения в разных условиях и схемах лазерного имитационного эксперимента в сравнении с реальными процессами в камерах тепловых машин из-за контактов рабочего вещества с их поверхностью. Предмет такого рассмотрения связан с тем, что в лазерных схемах можно относительно легко и регулируемым образом управлять их топологией в разных модификациях (в диапазоне 1D–3D структур, образующихся на поверхностях разной геометрической формы фрактального типа). Это дает большие возможности для изучения различных часто возникающих нежелательных случайных дефектов и неоднородностей сложной конфигурации с развитием неожидаемых процессов при динамических режимах работы энергетических установок разного типа в условиях их реальной эксплуатации и определяется с помощью геометрического анализа в рамках соответствующих нелинейных моделей с различными нелинейными фрактальными образами. Нами использовались в данном аспекте две модели для рассмотрения развития возникающих фрактальных трещиноватых структур: во-первых, диффузионное распространение/рост трещин разной геометрии с совокупностью локальных отрезков и фрагментов в различных направлениях; во-вторых, с диффузно-ограниченной агрегацией их распространения (Diffusion-Limited Aggregation – DLA) с использованием формализма клеточных автоматов в перколяционном приближении для разных алгоритмов образования фрактальных структур. Приведем только итоговые результаты расчетов без деталей их процедуры, что достаточно для наглядного и качественного определения процесса роста трещиноватости и дефектов. При этом конечной целью рассмотрения является изучение возникновения возможных и контролируемых локальных областей/коллекторов, начиная с поверхностных структур, и их ассоциация с реальными объектами на поверхности камер с рабочим веществом в энергосистемах. Обсуждается возможная практическая значимость подобного моделирования и анализа
Role of Vector Mesons in High-Q^2 Lepton-Nucleon Scattering
The possible role played by vector mesons in inclusive deep inelastic
lepton-nucleon scattering is investigated. In the context of the convolution
model, we calculate self-consistently the scaling contribution to the nucleon
structure function using the formalism of time-ordered perturbation theory in
the infinite momentum frame. Our results indicate potentially significant
effects only when the vector meson---nucleon form factor is very hard.
Agreement with the experimental antiquark distributions, however, requires
relatively soft form factors for the , and vertices.Comment: 22 pages, 9 figures (available upon request); accepted for
publication in Phys.Rev.D, ADP-92-197/T12
Recommended from our members
Data Archived for Events in the Caucasus for the CauSINCollaboration Project
The Causin project is a joint effort between the countries in the Caucasus region to develop a Probabilistic Seismic Hazard Analysis. To that end, we have compiled a database of all available network data in the region. The information contained in the database is from four countries: Armenia, Georgia, Azerbaijan, and Turkey and from the Incorporated Research Institutions for Seismology (IRIS). Table 1 lists the networks from which data were obtained. Figure 1 shows the locations of stations, and Figure 2 shows ray paths for event locations of the archived data. An ongoing effort in the region is the Caucasus Seismic Information Network (CauSIN) is an international scientific project enabling the countries and scientists of the region to: better understand the seismicity of the greater Caucasus; develop new monitoring networks to support the scientific understanding; provide access to seismic data from local networks in the participating countries; and develop a probabilistic seismic hazards assessment for the region enabling the governments in the region to better mitigate the damaging effects from large earthquakes. In parallel with this effort, training has been conducted on modern techniques for probabilistic hazards assessment. CauSIN is also an ongoing effort to promote cooperation in the geosciences between Georgia, Armenia, Azerbaijan, European Union and the United States. The DOE supports the American team from New England Research, Inc. (NER), Massachusetts Institute of Technology (MIT), Boston College, and Lawrence Livermore National Laboratory (LLNL)
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