In this proceedings, we present STAR's measurement of v 2 difference between positively charged pions and negatively charged pions at low transverse momentum for Au + Au collisions at √ s N N = 200 GeV. The integrated v 2 of π + (π − ), 0.15 < p T < 0.5 GeV/c, decreases (increases) linearly with the increasing charge asymmetry A ± . The v 2 difference between π + and π − is proportional to A ± and the slope parameters have their order of magnitude of about 0.01. All of these observed features are consistent with the predication based on Chiral Magnetic Wave. The centrality dependence of the v 2 difference is different than that was predicted.

The search for short-lived particles is usually the final stage in the chain of event reconstruction and precedes event selection when operating in online mode or physics analysis when operating in offline mode. Most often such short-lived particles are neutral and their search and reconstruction is carried out using their daughter charged particles resulting from their decay. The use of the missing mass method makes it possible to find and analyze also decays of charged short-lived particles, when one of the daughter particles is neutral and is not registered in the detector system. One of the most known examples of such decays is the decay Σ− → nπ−. In this paper, we discuss in detail the missing mass method, which was implemented as part of the KF Particle Finder package for the search and analysis of short-lived particles, and describe the use of the method in the STAR experiment (BNL, USA). The method was used to search for pion (π± → μ±ν) and kaon (K± → μ±ν and K± → π±π0) decays online on the HLT farm in the express production chain. An important feature of the express production chain in the STAR experiment is that it allows one to start calibration, production, and analysis of the data immediately after receiving them. Here, the particular features and results of the real-time application of the method within the express processing of data obtained in the BES-II program at a beam energy of 3.85 GeV/n when working with a fixed target are presented and discussed.

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 P∞ as an evaluation of the percolation threshold. The susceptibility, defined as the derivative of P∞, possess finite-size scaling property, where the scaling exponent is the reciprocal of ν -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 PQGP -the probability for the event with QGP formation. The finite-size scaling of its derivative can give the critical exponent ν, which is a rare case that can provide an experimental measure of a critical exponent in heavy ion collisions.

The search for short-lived particles is an important part of physics research in experiments withrelativistic heavy ions. To find, select and study the properties of such short-lived particles in real timein the CBM experiment (FAIR/GSI, Germany), we have developed a package of algorithms, KFParticle Finder, which contains a search for more than 150 decay channels. The decays of short-livedcharged particles, when one of the daughter particles is neutral and cannot be registered in the detectorsystem, are also of great physics interest. To find and study such decays, we have extended the KFParticle Finder package by implementing the missing mass method, which is based on theconservation of energy and momentum laws.The method was studied in detail on simulated data of the CBM experiment, showing high efficiencywith a large signal-to-background ratio, as well as high significance. As part of the FAIR Phase-0program, the KF Particle Finder package of algorithms has been adapted for online and offlineprocessing in the STAR experiment (BNL, USA).Here we describe and discuss in detail the missing mass method for finding and analyzing short-livedparticles. The features of the application of the method to both simulated data in the CBM experimentand in the STAR experiment as part of real-time express data processing, as well as the results of thereal-time reconstruction of short-lived particle decays in the BES-II environment of the STARexperiment, are given.