64 research outputs found
Analyses of multiplicity distributions by means of the Modified Negative Binomial Distribution and its KNO scaling function
We analyze various data of multiplicity distributions by means of the
Modified Negative Binomial Distribution (MNBD) and its KNO scaling function,
since this MNBD explains the oscillating behavior of the cumulant moment
observed in e^+e^- annihilations, h-h collisions and e-p collisions. In the
present analyses, we find that the MNBD(discrete distributions) describes the
data of charged particles in e^+e^- annihilations much better than the Negative
Binomial Distribution (NBD). To investigate stochastic property of the MNBD, we
derive the KNO scaling function from the discrete distribution by using a
straightforward method and the Poisson transform. It is a new KNO function
expressed by the Laguerre polynomials. In analyses of the data by using the KNO
scaling function, we find that the MNBD describes the data better than the
gamma function.Thus, it can be said that the MNBD is one of useful formulas as
well as NBD.Comment: 12 pages, latex, 3 figure
Local thermalization in d + Au collisions
The extent of a locally equilibrated parton plasma in d + Au collisions at
sqrt(s_NN) = 200 GeV is investigated as a function of centrality in a
nonequilibrium-statistical framework. Based on a three-sources model,
analytical solutions of a relativistic diffusion equation are in precise
agreement with recent data for charged-particle pseudorapidity distributions.
The moving midrapidity source indicates the size of the local thermal
equilibrium region after hadronization. In central d + Au collisions it
contains 19% of the produced particles.Comment: 4 pages, 1 figure, Proc. QM2005 Budapes
Analyses of multiplicity distributions with \eta_c and Bose-Einstein correlations at LHC by means of generalized Glauber-Lachs formula
Using the negative binomial distribution (NBD) and the generalized
Glauber-Lachs (GGL) formula, we analyze the data on charged multiplicity
distributions with pseudo-rapidity cutoffs \eta_c at 0.9, 2.36, and 7 TeV by
ALICE Collaboration and at 0.2, 0.54, and 0.9 TeV by UA5 Collaboration. We
confirm that the KNO scaling holds among the multiplicity distributions with
\eta_c = 0.5 at \sqrt{s} = 0.2\sim2.36 TeV and estimate the energy dependence
of a parameter 1/k in NBD and parameters 1/k and \gamma (the ratio of the
average value of the coherent hadrons to that of the chaotic hadrons) in the
GGL formula. Using empirical formulae for the parameters 1/k and \gamma in the
GGL formula, we predict the multiplicity distributions with \eta_c = 0.5 at 7
and 14 TeV. Data on the 2nd order Bose-Einstein correlations (BEC) at 0.9 TeV
by ALICE Collaboration and 0.9 and 2.36 TeV by CMS Collaboration are also
analyzed based on the GGL formula. Prediction for the 3rd order BEC at 0.9 and
2.36 TeV are presented. Moreover, the information entropy is discussed
Multiplicity dependence of identical particle correlations in the quantum optical approach
Identical particle correlations at fixed multiplicity are consideres in the
presence of chaotic and coherent fields. The multiplicity distribution,
one-particle momentum density, and two-particle correlation function are
obtained based on the diagrammatic representation for cmulants in
semi-inclusive events. Our formulation is applied to the analysis of the
experimental data on the multiplicity dependence of correlation functions
reported by the UA1 and the OPAL Collaborations.Comment: 14 pages, 7 figure
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