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QCD Phase Diagram from Finite Energy Sum Rules Alejandro Ayala Instituto de Ciencias Nucleares, UNAM (In collaboration with A. Bashir, C. Domínguez, E. Gutiérrez, M. Loewe, and A. Raya) arXiv:1106.5155 [hep-ph]
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Outline Deconfinement and chiral symmetry restoration Resonance threshold energy as phenomenological tool to study deconfinement QCD sum rules at finite temperature/chemical potential Results
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Deconfinement and chiral symmetry restoration Driven by same effect: With increasing density, confining interaction gets screened and eventually becomes less effective (Deconfinement) Inside a hadron, quark mass generated by confining interaction. When deconfinement occurres, generated mass is lost (chiral transition)
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Critical end point?
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Lattice quark condensate and Polyakov loop A. Bazavov et al., Phys. Rev. D 90, 014504 (2009)
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Status of phase diagram =0: Physical quark masses, deconfinement and chiral symmetry restoration coincide. Smooth crossover for 170 MeV < T c < 200 MeV Analysis tools: – Lattice (not applicable at finite ) – Models (Polyakov loop, quark condesate) Lattice vs. Models: – Lattices gives: smaller/larger chemical potential/temperature values for endpoint than models Critical end point might not even exist!
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Alternative signature: Melting of resonances s Im s0s0 pole For increasing T and/or B the energy threshold for the continuum goes to 0
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Correlator of axial currents
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Quark – hadron duality Operator product expansion Finite energy sum rules
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Non-pert part: dispersion relations
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Pert part: imaginary parts at finite T and Two contributions: 1)Annihilation channel (available also at T= =0) 2)Dispersion channel (Landau damping)
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Imaginary parts at finite T and Annihilation term Dispersion term Pion pole
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Threshold s 0 at finite T and GMOR N=1, C 2 = 0 2 Need quark condensate at finite T and
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quark condensate T, 0 Poisson summation formula quark condensate
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Parameters fixed by requiring S-D conditions and description of lattice data Lose of Lorentz covariance means that Parametrize S-D solution in terms of “free-like” propagators A. Bazavov et al., Phys. Rev. D 90, 014504 (2009)
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Representation makes it easy to carry out integration 2 8 _
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Susceptibilities
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QCD Phase Diagram
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Summary and conclusions QCD phase diagram rich in structure: critical end point? Polyakov loop, quark condensate analysis can be supplemented with other signals: look at threshold s 0 as function of T and Finite energy QCD sum rules provide ideal framework. Need calculation of quark condesnate. Use S-D quark propagator parametrized with “free- like” structures. Transition temperatures coincide, method not accurate enough to find critical point, stay tuned.
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