Long-range correlations between particles separated by a pseudorapidity gap are a powerful tool to explore the initial stages and evolution of the medium created in hadron-hadron collisions. An ...overview of the long-range correlations measured by the ALICE detector in pp, p-Pb and Pb-Pb will be presented. This includes analyses of forward-backward, two- and multi-particle correlations with the use of the central barrel and forward detectors.
It is shown that Principal Component Analysis (PCA) applied to event-by-event single-particle distributions in A–A collisions allows establishing the most optimal basis for anisotropic flow studies ...from data itself, in contrast to manual selection of the basis functions. PCA coefficients for azimuthal particle distributions are identical to Fourier coefficients from a conventional analysis techniques. PCA applied in longitudinal dimension reveals optimal basis that is similar to Legendre polynomial series. Analysis in both dimensions simultaneously allows studying the coupling of the longitudinal structure of events with the azimuthal anisotropy of particle emission.
We present studies of strange particle yields and correlations in pp collisions in the PYTHIA8 event generator by studying forward-backward correlations. Several key processes that give rise to these ...correlative effects are identified and manipulated to probe the fundamental properties of strange particle emitting sources. The sensitivity of strange particle production and correlations to PYTHIA's multiparton interaction, color reconnection, and explicit strangeness suppression are shown.
The Multi-Purpose Detector, to be operating at NICA, aims to study the phase diagram of strongly interacting matter at high baryonic densities. One of the sensitive tools to probe the critical ...behaviour is the analysis of event-by-event fluctuations. Strongly intensive observables are considered to be especially sensitive to the phase transitions as they suppress trivial volume fluctuations. In this contribution, we present the performance of the MPD detector in measurements of fluctuations via strongly intensive quantities between multiplicities and transverse momenta in different kinematic acceptances. The results from the full MPD simulation and reconstruction chains are demonstrated.
This paper presents the main results of studies which include both the search for new observables sensitive to novel physical phenomena expected in the formation of baryon rich dense matter formed in ...the collisions of heavy ions at NICA, and some practical solutions for selection of events with given mean energy density relevant to the number of binary nucleon–nucleon collisions. The behavior of strongly-intensive observables in the ranges of rapidity and momenta available for measurements at the MPD is presented, taking into account the response of the MPD experimental setup and reconstruction in the MpdRoot package. Methods of correction for track losses and inaccurate identification of particle species are discussed. The applicability of the standard Glauber model for the selection of centrality classes at the energies of the NICA collider is being critically reviewed. On the basis of MC simulated data and in accordance with the criteria of anticipated physical analysis, the possibilities of efficient event selection using a new fast detector system for beam–beam collisions monitoring are also briefly discussed.
The measurement of the production of deuterons, tritons and 3He and their antiparticles in Pb-Pb collisions at $\sqrt{s_{NN}}$= 5.02 TeV is presented in this article. The measurements are carried out ...at midrapidity (|y| < 0.5) as a function of collision centrality using the ALICE detector. The pT-integrated yields, the coalescence parameters and the ratios to protons and antiprotons are reported and compared with nucleosynthesis models. The comparison of these results in different collision systems at different center-of-mass collision energies reveals a suppression of nucleus production in small systems. In the Statistical Hadronisation Model framework, this can be explained by a small correlation volume where the baryon number is conserved, as already shown in previous fluctuation analyses. However, a different size of the correlation volume is required to describe the proton yields in the same data sets. The coalescence model can describe this suppression by the fact that the wave functions of the nuclei are large and the fireball size starts to become comparable and even much smaller than the actual nucleus at low multiplicities.
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