Self-similarity in Fluctuations and Clustering of Multiplicities

In this talk we summarize the main results of our recent publication [1], where we describe the observed by the CERN NA49 experiment a non-monotonic behavior of the fluctuations in multiplicity as a function of centrality of the collision using the concept of correlations between produced particles promoting cluster formation. A new element is a use of log-normal distribution for particles in a cluster which emerges naturally when one considers particle production based on bivariate branching scenario [2].

Effects of the detector non-uniformity in pion directed flow measurement relative to the spectator plane by the NA49 experiment at the CERN SPS

Results are presented for directed flow υ1 of negatively charged pions measured relative to the spectator plane in Pb+Pb collisions at the beam energy 40A GeV recorded by the NA49 experiment at CERN. The measurements were performed as a function of rapidity and transverse momentum in two classes of collision centrality. The projectile spectator symmetry plane is estimated using the transverse segmentation of the forward hadron calorimeters. Analysis details related to event selection and particle identification are provided along with a description of the procedure used to apply corrections for the limited detection efficiency. Additionally a systematic study of effects due to detector non-uniformity on pion directed flow measurement is presented.

Analysis of Anisotropic Transverse Flow in Pb–Pb Collisions at 40A GeV in the NA49 Experiment

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Procedure for Event Characterization in Pb-Pb Collisions at 40A GeV in the NA49 Experiment at the CERN SPS

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Elliptic Flow of π – Measured with the Event Plane Method in Pb–Pb Collisions at 40A Ge in the NA49 Experiment at the CERN SPS

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Procedure for event characterization in Pb-Pb collisions at 40AGeV in the NA49 experiment at the CERN SPS

The time evolution of the strongly interacting matter created in a heavy-ion collision depends on the initial geometry and the the centrality of the collision. Thus an experimental determination of the collision geometry is required. This paper discusses a procedure for event classification and estimation of the geometrical parameters in inelastic Pb+Pb collisions at a beam energy of 40A GeV recorded with the fixed target experiment NA49 at the CERN SPS. In the NA49 experiment, event classes can be defined using the measured multiplicity of particles in the Time Projection Chambers (TPC) or the energy of projectile spectators deposited in the forward Veto or Ring calorimeters. Using the Monte-Carlo Glauber model, these event classes can be related to average values of the geometric quantities such as impact parameter or number of nucleon-nucleon collisions. The implementation of this procedure within a software framework of the future CBM experiment was adopted for event classification in the NA49 experiment. In future, this procedure will be used for analysis of the new Pb+Pb data collected by the NA61/SHINE experiment and for comparison with the results previously obtained by STAR at RHIC and NA49 at the CERN SPS.

On Dynamical Net-Charge Fluctuations within a Hadron Resonance Gas Approach

The dynamical net-charge fluctuations (νdyn) in different particle ratiosK/π,K/p, andp/πare calculated from the hadron resonance gas (HRG) model and compared with STAR central Au+Au collisions atsNN=7.7–200 GeV and NA49 central Pb+Pb collisions atsNN=6.3–17.3 GeV. The three charged particle ratios (K/π,K/p, andp/π) are determined as total and average of opposite and average of the same charges. We find an excellent agreement between the HRG calculations and the experimental measurements, especially from STAR beam energy scan (BES) program, while the strange particles in the NA49 experiment at lower Super Proton Synchrotron (SPS) energies are not reproduced by the HRG approach. We conclude that the utilized HRG version seems to take into consideration various types of correlations including strong interactions through the heavy resonances and their decays especially at BES energies.