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Quarkonia spectral functions at zero and finite temperature Péter Petreczky Nuclear Theory Group and RIKEN-BNL Brookhaven National Laboratory Based on collaboration with: A. Jakovác (Budapest), K. Petrov (BNL) and A. Velytsky (UCLA) Motivations : Datta, Karsch, Petreczky, Wetzorke, PRD 69 (2004) 094507 Asakawa, Hatsuda, PRL 92 (04) 012001 What is the origin of the higher peaks ? What happens to 2S states ??
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Meson correlators and spectral functions Imaginary time Real time LGTExperiment, dilepton rate KMS condition
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Reconstruction of the spectral functions data and degrees of freedom to reconstruct Bayesian techniques: find which maximizes data Prior knowledge Maximum Entropy Method (MEM) Asakawa, Hatsuda, Nakahara, PRD 60 (99) 091503, Prog. Part. Nucl. Phys. 46 (01) 459 Likelihood function Shannon-Janes entropy : - default model - perturbation theory Constrained curve fitting: Lepage et al, hep-lat/0110175, Y. Chen et al, hep-lat/0405001
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x x Charmonia spectral functions on anisotropic lattices Anisotropic Fermilab action ( following P. Chen, PRD 64 (2001) 034509 ) Properties of the ground state are independent of the cut-off, higher peaks do depend on the cut-off Production: RBRC QCDOC test hardware
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What is the physics behind the 2 nd and higher peaks ??
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What is the physics behind the 2 nd and higher peaks ? Lattice spectral functions in the free theory, Karsch, Laerman, Petreczky, Stickan, PRD 68 (2003) 034008 spectral function at high energy is not described by the free theory, 2 nd and 3 rd peaks are part of distorted continuum. Finite lattice spacing effects are small in the correlator and their size is in accordance with expectations from the free field theory limit.
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Temperature dependence of charmonia correlators If spectral function do not change across : Potential model with screening : Mócsy, Petreczky hep-ph/0411262
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Charmonia spectral functions at finite temperature Large statistical errors !
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Temperature dependence of the correlators is independent of the cut-off ! 2S state does not melt ! Mócsy, Petreczky, hep-ph/0411262
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1S bottomonia states are dissolved at 1P bottomonia states are dissolved at Petrov, hep-lat/0503002
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Summary and Outlook Quarkonia spectral functions calculated on the lattice contain information about the properties of the lowest state, higher states do not correspond to states observed in nature 1S charmonia state can exist in the plasma up to temperatures while 1P states are dissociated at What to do with cut-off effects in the spectral functions at large energies ? SPF in free theory : Karsch, Laermann, Petreczky, Stickan, PRD 68 (03) 014504
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