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Search for the QCD critical point in ultrarelativistic ion collisions. Quark matter theory group, Department of Physics, University of Athens. Members of the group: N.G. Antoniou, F.K. Diakonos, A.I. Karanikas, C.N. Ktorides, X.N. Maintas (staff)
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Search for the QCD critical point in ultrarelativistic ion collisions Quark matter theory group, Department of Physics, University of Athens Members of the group: N.G. Antoniou, F.K. Diakonos, A.I. Karanikas, C.N. Ktorides, X.N. Maintas (staff) Y.F. Contoyiannis, A.S. Kapoyannis, G. Mavromanolakis, E. Saridakis (postdocs) N. Davis (PhD student), G. Tsolias (Msc student) NRC Demokritos, October 2010, NUPECC
The QCD phase diagram ( a simplified version) critical point From R. Casalbuoni, POS CPOD2006:001 (2006); hep-ph/0610179
Why it is important? B.L.Ioffe, Physics Uspekhi 49, 1077 (2006) Chiral condensation99% of the mass of the visible world (consituent quark mass) Thermodynamic properties of the QCD vacuum Hadronization F. Wilczek, hep-ph/0003183
Characteristics of the critical point • Order parameters • Universality class: 3-D Ising • Effective action at T=Tc (3 –D Ising) isoscalar sigma field net baryon density critical exponents: M. Stephanov, K. Rajagopal, E. Shuryak, Phys. Rev. Lett. 81, 4816 (1998) M.M. Tsypin, Phys. Rev. Lett. 73, 2015 (1994); J. Berges, N. Tetradis, C. Wetterich, Phys. Rev. Lett.77, 873 (1996)
Towards a critical point phenomenology Critical QCD Effective action adapted for describing the critical state produced in ultrarelativistic ion collisions (geometry and space time evolution) Thermodynamics of the critical effective action-local fluctuations (dominant instanton-like configurations, clusters with fractal geometry (DF)) Power-law density-density correlations (intermittency in factorial moments (F2 ~ MD-DF) critical opalescence) Critical Monte Carlo (CMC)
Publications N.G. Antoniou, F.K. Diakonos, C.N. Ktorides and M. Lahanas : Critical events and Intermittency in nuclear collisions, Phys. Lett.B 432, 8 (1998) N.G. Antoniou, Y.F. Contoyiannis, F.K. Diakonos and C.G. Papadopoulos : Fractals at T=Tc due to instantonlike configurations, Phys. Rev. Lett. 81, 4289 (1998) N.G. Antoniou, Y.F. Contoyiannis and F.K. Diakonos : The fractal geometry of critical systems, Phys. Rev. E 62, 3125 (2000) N.G. Antoniou, Y.F. Contoyiannis, F.K. Diakonos, A.I. Karanikas andC.N. Ktorides : Pion production from a critical QCD phase, Nucl. Phys.A 693, 799 (2001) N.G. Antoniou, Y.F. Contoyiannis, F.K. Diakonosand G. Mavromanolakis : Critical QCD in nuclear collisions, Nucl. Phys.A 761, 149 (2005) N.G. Antoniou, F.K. Diakonos, A.S. Kapoyannis and K.S. Kousouris: Critical opalescence in baryonic QCD matter, Phys. Rev. Lett.97, 032002 (2006)
The critical point in experiments with colliding nuclei • Analysis scheme for the detection of the critical point in real data based on observation of local fluctuations (guide: CMC) • Intermittency in transverse momentum space (F2(M)~ M2φ2) of: • dipions(π+π-)close to the production threshold • net baryons at midrapidity • Predictions of the intermittency exponents based on CQCD: • φ2 (dipions) =2/3 ; φ2(net baryons)=5/6 • (verified through CMC events)
Application to NA49 A+A data (CERN-SPS) (A=p,C,Si,Pb)(first indication of critical fluctuations in Si+Si)
Freeze-out states of existing experimental data Indication of divergent baryon number susceptibility isothermals
Publications N.G. Antoniou, F.K. Diakonos and A.S. Kapoyannis: The critical endpoint of bootstrap and lattice QCD matter, Nucl. Phys. A 759, 417 (2005) N.G. Antoniou, F.K. Diakonos and E.N. Saridakis: Evolution of critical correlations at the QCD phase transition, Nucl. Phys. A 784, 536 (2007) N.G. Antoniou, F.K. Diakonos and E.N. Saridakis: Evolutionary intermittency signaling the universality class of the QCD critical point, Phys. Rev. C 78, 024908 (2008) N.G. Antoniou, F.K. Diakonos and A.S. Kapoyannis:Indication for divergent baryon-number susceptibility in QCD matter, Phys. Rev.C 81, 011901 (2010) N.G. Antoniou, F.K. Diakonos, G. Mavromanolakis and the NA49 Collaboration: Search for the QCD critical point in nuclear collisions at the CERN SPS, Phys. Rev. C 81, 064907 (2010)
Future Plans • Scan both the baryonic and the isocalar sector in peripheral Pb+Pb collisions using NA49 data • Study the baryonic sector in C+C • Apply the same analysis in the forthcoming NA61/SHINE data
THEORETICALNUCLEARPHYSICS --- THEORETICAL NUCLEAR ASTROPHYSICS --- THEORYOF MANY BODY SYSTEMS --- THEORY OF COMPLEX SYSTEMS --- ARTIFICIAL INTELLIGENCE • Research programin the Departmentof Physics of the University of Athens since 1980 • Researchers: • E. Mavrommatis, F. Diakonos (permanent staff) • Collaborators at intervals (2000-2010): • M. Petraki, P. Papakonstantinou, P. Papachristou • S. Athanassopoulos,N. Costiris,G. Pavlou, A. Dakos • V. Constantoudis ( Demokritos), T. Kosmas (University of Ioannina) • C.C. Moustakidis (University of Thessaloniki), I. Lagaris (University of Ioannina) • J.W. Clark (Washington Univ., USA), J. Wambach, V.Yu Ponomarev (T.U., Darmstadt, Germany), O. Benhar (La Sapienza Univ., Italy), S. Fantoni (SISSA, Italy), • A. Fabrocini† (Pisa Univ., Italy), K.A. Gernoth (UMIST, UK), A Shebeko (Kharkov • Inst., Ukraine) H. Li (Darmoth C., USA)
THEORETICALNUCLEARPHYSICS Α. MICROSCOPIC THEORYOF MULTINUCLEON SYSTEMSStudy of correlations (short – range, long – range, pairing, complexity – chaos) Recent work: “Non linear classical model for the decay widths of isoscalar giant monopole resonances”P.K. Papachristou, E. Mavrommatis, V.Constantoudis,, F.K. Diakonos,J. Wambach,Phys. Rev.C77 (2008) 044305 “A CBF study of 1 0 superfluidity in dilute neutron matter”G. Pavlou, E. Mavrommatis, C.C.Moustakidis, J.W. Clark, in submission B.STATISTICAL MODELING OF NUCLEAR PROPERTIES WITH METHODS FROM STATISTICAL ANALYSISProgram: Pythagoras – Artificial Intelligence Modeling Site: www.pythaim.uoa.gr Recent work: “Nuclear mass systematics by complementing the finite range droplet model with neural networks”S. Athanassopoulos, E. Mavrommatis, K.A. Gernoth, J.W. Clark,in submission “Decoding β-decay systematics: A global statistical model for β–half -lives”N.J. Costiris, E. Mavrommatis,K.A. Gernoth, J.W. Clark, Phys. Rev.C80 (2009) 044332