Abstract The structure of events in relativistic heavy ion collisions (RHIC), associated with chiral QCD phase transition, is investigated. In particular the density fluctuations of pions, emitted from the excited vacuum (at T ≈ T c ), are studied and classified in terms of intermittency patterns in rapidity space. For this purpose a Monte Carlo simulation of critical events in the central region is presented, on the basis of the O (4) theory of chiral phase transition. The universal character of these events is revealed and the predictions of the theory are discussed in connection with event by event measurements in current and future experiments with relativistic heavy ions.

The role of strange quark mass in chiral QCD phase transition is examined, in the environment of relativistic nuclear collisions. The term in the effective potential of the O(4) universality class satisfies the stability requirement for a tricritical behaviour and can be used in order to study critical fluctuations in either side of the tricritical point . Comparing the corresponding patterns of density fluctuations in rapidity, one may distinguish the effects due to first- or second-order phase...

Last. W. Kittel(Radboud University Nijmegen)H-Index: 15

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Abstract Experimental data on particle correlations and fluctuations in various high-energy multiparticle collisions are presented, with special emphasis on evidence for scaling-law evolution in small phase-space domains. The notions of intermittency and fractality as related to the above findings are described. Phenomenological and theoretical work on the subject is reviewed.

#1N. G. Antoniou(UoA: National and Kapodistrian University of Athens)H-Index: 18

#2C. N. Ktorides(UoA: National and Kapodistrian University of Athens)H-Index: 9

Last. F.K. Diakonos(UCY: University of Cyprus)H-Index: 2

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Abstract The effective 3D action of the N -component φ 4 theory is adapted to the space-time hyperbolas of the critical multiparticle system, produced in relativistic ion collisions. In a systematic treatment of the ordered phase at T = T c , a strong intermittency pattern, with a minimal scale in rapidity, naturally emerges. The connection of the solution to chiral QCD phase transition is emphasized and its phenomenological implications are discussed.

Abstract Density fluctuations in small phase space bins for centrally produced particles are conveniently parametrized by a Gaussian free energy functional of the density fluctuation field. This observation leads to the investigation of the O( N ) linear σ-model; the O(4) version serves as a prototype theory of the QCD chiral order parameter. We derive an exact, non-perturbative and finite equation for its finite temperature effective action. In the large- N limit, well-known results on the natu...

This paper reports that an earlier suggestion that the chiral phase transition in QCD for two flavors of massless quarks might be a second-order transition has gained credibility as a result of recent numerical simulations. One can test this hypothesis, and draw very specific quantitative consequences from it, using universality and renormalization group ideas. This hypothetical second order phase transition is in the universality class of a four component isotropic Heisenberg antiferromagnet---...

Abstract It is proposed to study the dependence of factorial moments of the rapidity distribution on the size δy of the resolution. It is shown that if the fluctuations are purely statistical no variation of moments δy is expected, and thus observation of such a variation indicates the presence of genuine fluctuations of physical origin. The region in which the change occurs corresponds to the size (in rapidity) of the observed fluctuations. Intermittency, i.e. fluctuations of many different siz...

We employ the recently introduced Ising-QCD partition function (N.~G. Antoniou {\it et al.}, Phys. Rev. D 97, 034015 (2018)) to explore in detail the behaviour of the moments of the baryon-number, within the critical region around the critical endpoint. Our analysis is based on the relation of finite-size scaling in real space with intermittency in transverse momentum space. It demonstrates in practice the recent observation (N.~G. Antoniou {\it et al.}, Phys. Rev. D 97, 034015 (2018)) that comb...

This work presents the Levy index analysis of target protons emitted from 32S–AgBr (at 200 A GeV) and 16O–AgBr (at 60 A GeV) interactions using the G-moment (frequency moment) technique applied in the cosθ phase space. The observations are discussed in view of a thermal versus non-thermal phase transition.

Most signatures of new physics have been studied on the transverse plane with respect to the beam direction at the LHC where background is much reduced. In this paper we propose the analysis of inclusive longitudinal (pseudo)rapidity correlations among final-state (charged) particles in order to search for (un)particles belonging to a hidden sector beyond the Standard Model, using a selected sample of p–p minimum bias events (applying appropriate off-line cuts on events based on, e.g. minijets, ...

Results are presented on event-by-event fluctuations in transverse momentum of charged particles, produced at forward rapidities in p+p, C+C, Si+Si, and Pb+Pb collisions at 158 AGeV. Three different characteristics are discussed: the average transverse momentum of the event, the {phi}{sub p{sub T}} fluctuation measure, and two-particle transverse momentum correlations. In the kinematic region explored, the dynamical fluctuations are found to be small. However, a significant system size dependenc...

#1N.G. Antoniou(UoA: National and Kapodistrian University of Athens)H-Index: 2

#2A. S. Kapoyannis(UoA: National and Kapodistrian University of Athens)H-Index: 16

Abstract It is shown that hadronic matter formed at high temperatures, according to the prescription of the statistical bootstrap principle, develops a critical point at nonzero baryon chemical potential. The location of the critical point in the phase diagram, however, depends on the detailed knowledge of the partition function of the deconfined phase, near the critical line. In a simplified version of the quark–gluon partition function, the resulting location of the critical point is compared ...

#1N. G. Antoniou(UoA: National and Kapodistrian University of Athens)H-Index: 5

#2Yiannis Contoyiannis(UoA: National and Kapodistrian University of Athens)H-Index: 19

Last. C. N. Ktorides(UoA: National and Kapodistrian University of Athens)H-Index: 9

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Abstract A theoretical scheme which relates multiparticle states generated in ultrarelativistic nuclear collisions to a QCD phase transition is considered in the framework of the universality class provided by the 3D Ising model. Two different evolution scenarios for the QGP system are examined. The statistical mechanics of the critical state is accounted for in terms of (critical) cluster formation consistent with suitably cast effective action functionals, one for each considered type of expan...