124 research outputs found
Identification of Colour Reconnection using Factorial Correlator
A new signal is proposed for the colour reconnection in the hadronic decay of
W+ W- in e+e- collisions. Using Pythia Monte Carlo it is shown that this
signal, being based on the factorial correlator, is more sensitive than the
ones using only averaged quantities.Comment: 6 pages 1 postscript figur
Critical phenomena in disc-percolation model and its application to relativistic heavy ion collisions
Through studying the critical phenomena in continuum-percolation of discs, we
find a new approach to locate the critical point, i.e. using the inflection
point of as an evaluation of the percolation threshold. The
susceptibility, defined as the derivative of , possess finite-size
scaling property, where the scaling exponent is the reciprocal of -- the
critical exponent of correlation length. The possible application of this
approach to the study of the critical phenomena in relativistic heavy ion
collisions is discussed. The critical point for deconfinement can be extracted
by the inflection point of -- the probability for the event with
QGP formation. The finite-size scaling of its derivative can give the critical
exponent , which is a rare case that can provide an experimental measure
of a critical exponent in heavy ion collisions.Comment: 5 pages, 7 figure
Trace initial interaction from final state observable in relativistic heavy ion collisions
In order to trace the initial interaction in ultra-relativistic heavy ion
collision in all azimuthal directions, two azimuthal multiplicity-correlation
patterns -- neighboring and fixed-to-arbitrary angular-bin correlation patterns
-- are suggested. From the simulation of Au + Au collisions at 200 GeV by using
the Monte Carlo models RQMD with hadron re-scattering and AMPT with and without
string melting, we observe that the correlation patterns change gradually from
out-of-plane preferential one to in-plane preferential one when the centrality
of collision shifts from central to peripheral, meanwhile the anisotropic
collective flow v_2 keeps positive in all cases. This regularity is found to be
model and collision energy independent. The physics behind the two opposite
trends of correlation patterns, in particular, the presence of out-of-plane
correlation patterns at RHIC energy, are discussed.Comment: 5pages, 4figure
Levy Stability Index from Multifractal Spectrum
A method for extracting the Levy stability index from the multi-fractal
spectrum in high energy multiparticle production is proposed. This
index is an important parameter, characterizing the non-linear behaviour of
dynamical fluctuations in high energy collisions. Using the random cascading
model as example, the validity of this method is tested. It is shown
that this method, basing on a linear fit, is consistent with and more accurate
than the usual method of fitting the ratio of th to 2nd order multi-fractal
(R\'enyi) dimensions to the Peschanski formula.Comment: 7 pages 4 PS figures Record-No: HZPP-980
Entropy Analysis in \pi^{+}\rp and \rK^{+}\rp Collisions at GeV
The entropy properties are analyzed by Ma's coincidence method in
\pi^{+}\rp and \rK^{+}\rp collisions of the NA22 experiment at 250 GeV/
incident momentum. By using the R\'{e}nyi entropies, we test the scaling law
and additivity properties in rapidity space. The behavior of the R\'{e}nyi
entropies as a function of the average number of particles is investigated. The
results are compared with those from the {\sc Pythia} Monte Carlo event
generator.Comment: LaTeX, 11 pages, 5 figure to be appeared in Acta Phys. Pol.
Frequent occurrence of unreduced gametes in Triticum turgidum-Aegilops tauschii hybrids.
Abstract Spontaneous chromosome doubling via union of unreduced (2n) gametes has been thought to be the way that common wheat (Triticum aestivum L.) was originated from the hybridization of T. turgidum L. with Ae. tauschii Cosson. Previous works have observed unreduced gametes in F 1 hybrids of Ae. tauschii with six of the eight T. turgidum subspecies. It is not clear, however, whether the formation of these unreduced gametes is a norm in the F 1 hybrids. In the present study, we tried to answer this question by assessing the occurrence frequency of unreduced gametes in 115 T. turgidum-Ae. tauschii hybrid combinations, involving 76 genotypes of seven T. turgdium subspecies and 24 Ae. tauschii accessions. Our data show that these hybrid combinations differed significantly (P B 0.01, F = 11.40) in selfed seedset, an indicator for production of unreduced gametes. This study clearly showed that meiotic restitution genes are widely distributed within T. turgidum. However, significant differences were found between as well as within T. turgidum subspecies and in the interaction of the T. turgidum genotypes with those of Ae. taushii. The possible application of the meiotic restitution genes from T. turgidum in production of double haploids is also discussed
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