430 research outputs found
Energy Conservation Constraints on Multiplicity Correlations in QCD Jets
We compute analytically the effects of energy conservation on the
self-similar structure of parton correlations in QCD jets. The calculations are
performed both in the constant and running coupling cases. It is shown that the
corrections are phenomenologically sizeable. On a theoretical ground, energy
conservation constraints preserve the scaling properties of correlations in QCD
jets beyond the leading log approximation.Comment: 11 pages, latex, 5 figures, .tar.gz version avaliable on
ftp://www.inln.unice.fr
Generalised Factorial Moments and QCD Jets
{ In this paper we present a natural and comprehensive generalisation of the
standard factorial moments (\clFq) analysis of a multiplicity distribution.
The Generalised Factorial Moments are defined for all in the complex plane
and, as far as the negative part of its spectrum is concerned, could be useful
for the study of infrared structure of the Strong Interactions Theory of high
energy interactions (LEP multiplicity distribution under the ). The
QCD calculation of the Generalised Factorial Moments for negative is
performed in the double leading log accuracy and is compared to OPAL
experimental data. The role played by the infrared cut-off of the model is
discussed and illustrated with a Monte Carlo calculation. }Comment: 11pages 4 figures uuencode, LATEC, INLN 94/
Total Cross Section, Inelasticity and Multiplicity Distributions in Proton -- Proton Collisions
Multiparticle production in high energy proton -- proton collisions has been
analysed in the frame of Strongly Correlated Quark Model (SCQM) of the hadron
structure elaborated by the author. It is shown that inelasticity decreases at
high energies and this effect together with the total cross section growth and
the increasing with collision energy the masses of intermediate clusters result
in the violation of KNO -- scaling.Comment: 21 pages, 11 figures, submitted to Yad. Fisik
Comportamento fenologico e produtivo das variedades de uva 'Ribol' e 'Superior Seedless' na regiao de Jaboticabal, SP.
A introducao de novas variedades de videira e o estudo de seu comportamento e adaptacao nas diferentes regioes produtoras do pais constituem em importante alternativa para oferecer frutos diferenciados e de elevada qualidade aos consumidores, contribuindo para aumentar a lucratividade da atividade viticola. Realizou-se este trabalho com o objetivo de estudar o comportamento agronomico, fenologico e as exigencias termicas das variedades Ribol e Superior Seedless na regiao de Jaboticabal, SP. A variedade Ribol destacou-se com elevada producao/planta, boas caracteristicas de cacho e periodo fenologico de poda a colheita de 150 dias, apresentando-se com potencial para o cultivo na regiao Oeste do estado de Sao Paulo. A variedade Superior Seedless, apesar das boas caracteristicas dos cachos, apresentou produtividade muito baixa, necessitando de maiores estudos para ajuste da tecnologia de producao
Intermittency in Branching Processes
We study the intermittency properties of two branching processes, one with a
uniform and another with a singular splitting kernel. The asymptotic
intermittency indices, as well as the leading corrections to the asymptotic
linear regime are explicitly computed in an analytic framework. Both models are
found to possess a monofractal spectrum with . Relations with
previous results are discussed.Comment: 20 pages, UCLA93/TEP/2
Search for Neutral Q-balls in Super-Kamiokande II
A search for Q-balls induced groups of successive contained events has been
carried out in Super-Kamiokande II with 541.7 days of live time.
Neutral Q-balls would emit pions when colliding with nuclei, generating a
signal of successive contained pion events along a track. No candidate for
successive contained event groups has been found in Super-Kamiokande II, so
upper limits on the possible flux of such Q-balls have been obtained.Comment: 5 pages, 5 figures, Submitted to Phys. Lett.
J/Psi Suppression in Heavy Ion Collisions at the CERN SPS
We reexamine the production of J/Psi and other charmonium states for a
variety of target-projectile choices at the SPS. For this study we use a newly
constructed cascade code LUCIFER II, which yields acceptable descriptions of
both hard and soft processes, specifically Drell-Yan and hidden charm
production, and soft energy loss and meson production, at the SPS. Glauber
calculations of other authors are redone, and compared directly to the cascade
results. The modeling of the charmonium states differs from that of earlier
workers in its unified treatment of the hidden charm meson spectrum, which is
introduced from the outset as a set of coupled states. The result is a
description of the NA38 and NA50 data in terms of a conventional hadronic
picture. The apparently anomalous suppression found in the most massive Pb+Pb
system arises from three sources: destruction in the initial nucleon-nucleon
cascade, use of coupled channels to exploit the larger breakup in the less
bound Chi and Psi' states, and comover interaction in the final low energy
phase.Comment: 36 pages (15 figures
Dynamical Pion Production via Parametric Resonance from Disoriented Chiral Condensate
We discuss a dynamical mechanism of pion production from disoriented chiral
condensates (DCC). It leads to an explosive production of pions via the
parametric amplification mechanism, which is similar to the reheating mechanism
in inflationary cosmology. Classically, it is related with the instability in
the solutions of the Mathieu equation and we explore the quantum aspects of the
mechanism. We show that nonlinearlities and back reactions can be ignorable for
sufficiently long time under the small amplitude approximations of background
oscillations, which may be appropriate for the late stage of
nonequilibrium phase transition. It allows us to obtain an explicit quantum
state of the produced pions and , the squeezed state of BCS type.
Single particle distributions and two-pion correlation functions are computed
within these approximations. The results obtained illuminate the characteristic
features of multi-pion states produced through the parametric amplification
mechanism. In particular, two-pion correlations of various charge combinations
contain back-to-back correlations which cannot be masked by the identical
particle interference effect.Comment: REVTEX 18 pages and 10 figure
Wheat-barley hybridization – the last forty years
Abstract Several useful alien gene transfers have
been reported from related species into wheat (Triticum
aestivum), but very few publications have dealt
with the development of wheat/barley (Hordeum
vulgare) introgression lines. An overview is given
here of wheat 9 barley hybridization over the last
forty years, including the development of
wheat 9 barley hybrids, and of addition and translocation
lines with various barley cultivars. A short
summary is also given of the wheat 9 barley hybrids
produced with other Hordeum species. The meiotic
pairing behaviour of wheat 9 barley hybrids is presented,
with special regard to the detection of wheat–
barley homoeologous pairing using the molecular
cytogenetic technique GISH. The effect of in vitro
multiplication on the genome composition of intergeneric
hybrids is discussed, and the production and
characterization of the latest wheat/barley translocation
lines are presented. An overview of the agronomical
traits (b-glucan content, earliness, salt tolerance,
sprouting resistance, etc.) of the newly developed
introgression lines is given. The exploitation and
possible use of wheat/barley introgression lines for
the most up-to-date molecular genetic studies
(transcriptome analysis, sequencing of flow-sorted
chromosomes) are also discussed
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