450 research outputs found
Measuring the Charged Particle Multiplicity with ALICE
The charged particle multiplicity distribution is one of the first
measurements that ALICE will be able to perform. The knowledge of this basic
property at a new energy is needed to configure Monte Carlo generators
correctly with the aim of understanding the background of other, especially
rare, processes including new physics. It allows to study the scaling behaviour
and to verify model predictions. The unfolding of the measurement is a
non-trivial task due to the finite precision and acceptance of the detector.
Solutions are based on chi2 minimization or iteratively using Bayes' theorem.
Both approaches to unfold the spectrum are presented. Furthermore, the
capabilities of the SPD fast OR trigger are shown that enable physics at very
high multiplicities.Comment: Proceedings of poster presentation at Quark Matter 2008, 20th
International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions in
Jaipur, India; to be published in Indian Journal of Physics; 4 pages, 4
figure
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
Jet Energy Density in Hadron-Hadron Collisions at High Energies
The average particle multiplicity density dN/deta is the dynamical quantity
which reflects some regularities of particle production in low-pT range. The
quantity is an important ingredient of z-scaling. Experimental results on
charged particle density are available for pp, pA and AA collisions while
experimental properties of the jet density are still an open question. The goal
of this work is to find the variable which will reflect the main features of
the jet production in low transverse energy range and play the role of the
scale factor for the scaling function psi(z) and variable z in data
z-presentation. The appropriate candidate is the variable we called "scaled jet
energy density". Scaled jet energy density is the probability to have a jet
with defined ET in defined xT and pseudorapidity regions. The PYTHIA6.2 Monte
Carlo generator is used for calculation of scaled jet energy density in
proton-proton collisions over a high energy range (sqrt s = 200-14000 GeV) and
at eta = 0. The properties of the new variable are discussed and sensitivity to
"physical scenarios" applied in the standard Monte Carlo generator is noted.
The results of scaled jet energy density at LHC energies are presented and
compared with predictions based on z-scaling.Comment: 11 pages, LaTeX, 8 figures, Presented at the XVII International
Baldin Seminar on High Energy Physics Problems "Relativistic Nuclear Physics
& Quantum Chromodynamics", Dubna, Russia, September 27 - October 2, 200
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
Scaling Distributions of Quarks, Mesons and Proton for all , Energy and Centrality
We present the evidences for the existence of a universal scaling behavior of
the production of at all transverse momenta in heavy-ion collisions at
all centralities and all collision energies. The corresponding scaling behavior
of the quarks is then derived just before the quarks recombine with antiquarks
to form the pions. The degradation effect of the dense medium on the quark
is derived from the scaling distribution. In the recombination model it
is then possible to calculate the distributions of the produced proton
and kaon, which are scaling also. Experimentally verifiable predictions are
made. Implications of the existence of the scaling behavior are discussed.Comment: 10 pages in RevTeX, including 14 figures in eps file
Novel Scaling Behavior for the Multiplicity Distribution under Second-Order Quark-Hadron Phase Transition
Deviation of the multiplicity distribution in small bin from its
Poisson counterpart is studied within the Ginzburg-Landau description for
second-order quark-hadron phase transition. Dynamical factor for the distribution and ratio are defined, and
novel scaling behaviors between are found which can be used to detect the
formation of quark-gluon plasma. The study of and is also very
interesting for other multiparticle production processes without phase
transition.Comment: 4 pages in revtex, 5 figures in eps format, will be appeared in Phys.
Rev.
HISTORY AND RESULTS OF THE INTRODUCTION OF PALMS (ARECACEAE C.H. SCHULTZ) ON THE SOUTHERN COAST OF THE CRIMEA
The results of the introduction of palms have been summarized, and the assortment, opportunities and conditions of their cultivation on the Southern Coast of the Crimea (SCC) defined. Long-term observations on the experimental plants with an assessment of their prospects according to a frosting scale during severe winters and biometric measurements of their habit by instrumental methods have been conducted. The article describes the history and results of the palms' introduction beginning from 1814 up to the present moment. It was established that growth and development of palms in the NBG's arboretum depend not only on their winter resistance but also on the growing conditions and cultivation practices. The results of the palms' introduction over a 30-year span of the research (1984-2014) through the example of their growth and development in the NBG's arboretum have been summed up. The data about the characteristic habits and reproductive capabilities for the year 1984 have been provided and compared with the same parameters obtained in 2014 on the same experimental trees. A picture of actual damages of various palm species during severe winters has been shown, and the degree of their tolerance to extreme negative temperatures determined. A promising assortment of palms tested in the NBG's arboretum has been identified, and the conditions of their cultivation on the SCC shown. The environmental and biological criteria influencing growth and development of 12 species of palms have been defined. Recommendations as to agricultural practices, protection in winter, and rational utilization of palms in ornamental gardening have been provided
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
Disoriented Chiral Condensates, Pion Probability Distributions and Parallels with Disordered System
A general expression is discussed for pion probability distributions coming
from relativistic heavy ion collisions. The general expression contains as
limits: 1) The disoriented chiral condensate (DCC), 2) the negative binomial
distribution and Pearson type III distribution, 3) a binomial or Gaussian
result, 4) and a Poisson distribution. This general expression approximates
other distributions such as a signal to noise laser distribution. Similarities
and differences of the DCC distribution with these other distribution are
studied. A connection with the theory of disordered systems will be discussed
which include spin-glasses, randomly broken objects, random and chaotic maps.Comment: 5 pages, 1 figure include
Heavy quark flavour dependence of multiparticle production in QCD jets
After inserting the heavy quark mass dependence into QCD partonic evolution
equations, we determine the mean charged hadron multiplicity and second
multiplicity correlators of jets produced in high energy collisions. We thereby
extend the so-called dead cone effect to the phenomenology of multiparticle
production in QCD jets and find that the average multiplicity of heavy-quark
initiated jets decreases significantly as compared to the massless case, even
taking into account the weak decay products of the leading primary quark. We
emphasize the relevance of our study as a complementary check of -tagging
techniques at hadron colliders like the Tevatron and the LHC.Comment: Version revised, accepted for publication in JHEP, 21 pages and 7
figure
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