941 research outputs found
Recent results from NA61/SHINE and NA49
Preliminary results on particle spectra and fluctuations in inelastic p+p
interactions measured by NA61/SHINE at the CERN SPS are presented and its
future ion program is discussed. We also show results on the excitation
functions of event-by-event particle ratio fluctuations in central Pb+Pb
collisions from NA49 using a novel approach. We found a dependence of the
results on phase space coverage which appears to explain the reported
difference between measurements of NA49 and those of STAR in central Au+Au
collisions
Multiplicity Fluctuations of Identified Hadrons in Central Pb+Pb Collisions at the CERN
We report on the event-by-event multiplicity fluctuations of identified particles in central Pb+Pb collisions measured by the NA49 experiment at the CERN SPS. Employing a novel approach we unfolded the moments of the unknown multiplicity distributions of protons (p), kaons (K), pions (π) and electrons. Using these moments we reconstructed an excitation function of the fluctuation measure νdyn[A;B], with A and B denoting different particle types. Specifically, we reconstructed νdyn for the [p, π], [p, K] and [K, π] pairs. The energy dependence of νdyn is in agreement with previously published NA49 results on the related measure σdyn. Moreover, for [K; p] and [K;p] pairs, we discovered a dependence of the fluctuation measure νdyn on the phase space coverage (acceptance). Interestingly for the [p,π] case no significant acceptance dependence was observed. These observations provide a likely explanation of the reported differences between measurements of NA49 and those of STAR in central Au+Au collisions
A model-free procedure to correct for volume fluctuations in E-by-E analyses of particle multiplicities
We develop an innovative and unbiased procedure, based on event mixing, to
account for unavoidable contributions from volume (or system size) fluctuations
to experimentally measured moments of particle multiplicity distributions
produced in relativistic nuclear collisions. Within the wounded-nucleon model
they are characterized by fluctuations of the number of wounded nucleons, the
latter usually referred to as participants. For the first time we extract
participant fluctuations directly from the data used for the fluctuation
analysis, i.e., without involving model calculations. To achieve this we
constructed a dedicated event-mixing algorithm that eliminates all possible
correlations between produced particles while preserving the volume
fluctuations. The procedure provides direct access to the cumulants of
wounded-nucleon distributions, which can be used to account for non-critical
contributions to the experimentally measured cumulants of multiplicity
distributions
QCD under extreme conditions
In nucleus-nucleus collisions at relativistic energies a new kind of matter
is created, the Quark-Gluon Plasma (QGP). The phase diagram of such matter and
the chemical freeze-out points will be presented in connection to the
pseudo-critical temperature for the chiral cross over transition. The role of
conserved charge fluctuations to give experimental access to the nature of the
chiral phase transition will be summarized in terms of the relation to lattice
QCD and the current experimental data. The QGP can be characterized as a nearly
ideal liquid expanding hydrodynamically and the experimental data allow to
extract transport parameters such as the bulk and shear viscosities. The energy
loss of partons in the QGP probes the high parton density of the medium. The
role of quarkonia and open charm hadrons as a probe of deconfinement and
hadronization form the final topic.Comment: Article to appear in a special EPJC Volume in celebration of '50
Years of Quantum Chromodynamics' [arXiv:2212.11107
Psychometric Evaluation of the Satisfaction With Life Scale (SWLS) in Azerbaijan
The Satisfaction With Life Scale (SWLS) is a globally recognized scale for the measurement of subjective well-being in more than thirty six languages. Currently there is no adapted version of the SWLS in Azerbaijani language. The aim of the present study was to complete forward and backward translations of the SWLS and maintaining equivalence to examine its psychometric properties in a sample of 374 subjects in Azerbaijan. The results showed that the Azerbaijani version of SWLS had good internal consistency (Cronbach’s α = 0.81) with confirmatory factor analysis showing a single factorial structure. The findings suggest that theAzerbaijani version of the SWLS is a valid instrument to use among Azerbaijan samples
Methods to analysis of queueing models with state-dependent jump priorities
In this paper, exact and approximate approaches for studying queuing
models with state-dependent jump priorities are developed. Both models
with finite separate buffers and finite common buffer for heterogeneous calls
are investigated. It is shown that both models might be described by twodimensional
Markov Chains (2-D MC). Exact approach based on solution of
appropriate system of balance equations (SBE) for state probabilities faced
with big computational challenges for large scale models. To overcome the indicated
difficulties an approximate approach based on the state space merging
algorithms is developed. This approach allows to construct simple algorithms
to calculate the Quality of Service (QoS) metrics of the examined models. The
results of numerical experiments are demonstrated
Study of exclusive one-pion and one-eta production using hadron and dielectron channels in pp reactions at kinetic beam energies of 1.25 GeV and 2.2 GeV with HADES
We present measurements of exclusive ensuremathπ+,0 and η production in pp reactions at 1.25GeV and 2.2GeV beam kinetic energy in hadron and dielectron channels. In the case of π+ and π0 , high-statistics invariant-mass and angular distributions are obtained within the HADES acceptance as well as acceptance-corrected distributions, which are compared to a resonance model. The sensitivity of the data to the yield and production angular distribution of Δ (1232) and higher-lying baryon resonances is shown, and an improved parameterization is proposed. The extracted cross-sections are of special interest in the case of pp → pp η , since controversial data exist at 2.0GeV; we find \ensuremathσ=0.142±0.022 mb. Using the dielectron channels, the π0 and η Dalitz decay signals are reconstructed with yields fully consistent with the hadronic channels. The electron invariant masses and acceptance-corrected helicity angle distributions are found in good agreement with model predictions
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