976 research outputs found
Search for a signal on intermediate baryon systems formation in hadron-nuclear and nuclear-nuclear interactions at high energies
We have analyzed the behavior of different characteristics of hadron-nuclear
and nuclear-nuclear interactions as a function of centrality to get a signal on
the formation of intermediate baryon systems. We observed that the data
demonstrate the regime change and saturation. The angular distributions of slow
particles exhibit some structure in the above mentioned reactions at low
energy. We believe that the structure could be connected with the formation and
decay of the percolation cluster. With increasing the mass of colliding nuclei,
the structure starts to become weak and almost disappears ultimately. This
shows that the number of secondary internuclear interactions increases with
increasing the mass of the colliding nuclei. The latter could be a reason of
the disintegration of any intermediate formations as well as clusters, which
decrease their influence on the angular distribution of the emitted particles.Comment: 2 pages and one figur
Analysis of nucleus-nucleus collisions at high energies and Random Matrix Theory
We propose a novel statistical approach to the analysis of experimental data
obtained in nucleus-nucleus collisions at high energies which borrows from
methods developed within the context of Random Matrix Theory. It is applied to
the detection of correlations in momentum distributions of emitted particles.
We find good agreement between the results obtained in this way and a standard
analysis based on the method of effective mass spectra and two-pair correlation
function often used in high energy physics. The method introduced here is free
from unwanted background contributions.Comment: 11 pages, 10 figure
First hours of the GRB 030329 optical afterglow
We present the first results of the observations of the extremely bright
optical afterglow of gamma-ray burst (GRB) 030329 with the 1.5m Russian-Turkish
telescope RTT150 (TUBITAK National Observatory, Bakyrlytepe, Turkey). RTT150
was one of the first 1.5m-class telescopes pointed to the afterglow.
Observations were started approximately 6 hours after the burst. During the
first 5 hours of our observations the afterglow faded exactly as a power law
with index -1.19+-0.01 in each of the BVRI Bessel filters. After that, in all
BVRI filters simultaneously we observe a steepening of the power law light
curve. The power law decay index smoothly approaches the value ~= -1.9,
observed by other observatories later. This power law break occurs at t-t_0
=0.57 days and lasts for +-0.1 days. We observe no variability above the
gradual fading with the upper limits 10--1% on time scales 0.1--1000s. Spectral
flux distribution in four BVRI filters corresponds to the power law spectrum
with spectral index \alpha=0.66+-0.01. The change of the power law decay index
in the end of our observations can be interpreted as a signature of collimated
ultrarelativistic jet. The afterglow flux distribution in radio, optical and
x-rays is consistent with synchrotron spectrum. We continue our observations of
this unique object with RTT150.Comment: Astronomy Letters, Vol. 29, No. 9, p. 573; 6 pages, 5 figures;
pagination corrected; the original Russian version can be found at
http://hea.iki.rssi.ru/~br/030329/pfh030329.pd
Some Properties of the Central pi--Meson Carbon Interactions at 40 Gev/C
We discuss some properties of the central pi--meson carbon reactions at 40
GeV/c. While these results were obtained many years ago they have not been
explained completely. We attempt to interpret following: results regime change
on the behavior of some characteristics of the events as a function of the
centrality; anomaly peak on the angular distributions of the slow protons
emitted in these reactions; charge asymmetry on the pi--mesons production in
the back hemisphere in lcs.
Understanding of the results could help to explain the new ones coming from
the modern central experiments at high and ultrarelativistic energies.Comment: To appear in the proceedings of the 10th nternational Workshop on
Meson Production, Properties and Interaction (MESON 2008), Krakow, Poland, 6
- 10 June 2008. 4 pages and 4 figure
- …