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Xiao-Ming Xu Collaborator: Jie Zhou PowerPoint Presentation
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Xiao-Ming Xu Collaborator: Jie Zhou

Xiao-Ming Xu Collaborator: Jie Zhou

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Xiao-Ming Xu Collaborator: Jie Zhou

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  1. Temperature-dependent cross sectionsfor charmonium dissociation in collisions with pions and rhos in hadronic matter Xiao-Ming Xu Collaborator: Jie Zhou

  2. phenomena:(a) J/ suppression in a heavy ion collision;(b) J/  enhancement in some momentum region. Dissociation mechanisms (color screening, charmonium dissociation in collisions with gluons, charmonium dissociation in collisions with hadrons), recombination mechanism and nuclear parton shadowing build various models to explain the phenomena.

  3. J/ suppression reasons: Color screening (T. Matsui, H. Satz, Phys. Lett. B178 (1986) 416) Dissociated by a gluon (M.E. Peskin, Nucl. Phys. B156 (1979) 365; G. Bhanot, M.E. Peskin, Nucl. Phys. B156 (1979) 391; D. Kharzeev, H. Satz, Phys. Lett. B334 (1994) 155) Dissociated by a hadron (J. Ftacnik et al., Phys. Lett. B207 (1988) 194; S. Gavin et al., Phys. Lett. B207 (1988) 257; R. Vogt et al., Phys. Lett. B207 (1988) 263; C. Gerschel et al., Phys. Lett. B207 (1988) 253) J/ + hadron  charmed mesons (charmed baryons) Nuclear shadowing

  4. J/ enhancement reason recombination mechanism X.-M. Xu, Nucl. Phys. A658 (1999) 165; P. Braun-Munzinger, J. Stachel, Phys. Lett. B490 (2000) 196; R.L. Thews, M. Schroedter, J. Rafelski, Phys. Rev. C63 (2001) 054905

  5. Evidence of nuclear shadowing at LHCX.-M. Xu, Nucl. Phys. A697 (2002) 825; CMS-HIN-10-006

  6. evidence of the recombination mechanism at LHCCMS-HIN-10-006

  7. quark model calculations: K. Martins et al., Phys. Rev. C51 (1995) 2723 C.-Y. Wong et al., Phys. Rev. C65 (2001) 014903 T. Barnes et al., Phys. Rev. C68 (2003) 014903 X.-M. Xu et al., Nucl. Phys. A713 (2003) 470 ············ meson exchange model calculations: S.G. Matinyan, B. Muller, Phys. Rev. C58 (1998) 2994 K .Haglin, Phys. Rev. C61 (2000) 031902 Z. Lin, C.M. Ko, Phys. Rev. C62 (2000) 034903 ············ For J/ + hadron  charmed mesons (charmed baryons),early works assumed that hadron-charmonium dissociation cross sections are constants; quark model calculations or meson exchange model calculations have obtained the dissociation cross sections that depend on the center-of-mass energy of J/ and hadron.

  8. problem What is the temperature dependence of hadron-charmonium dissociation cross sections?

  9. Prior form: gluon propagation before quark interchange

  10. Post form: gluon propagation after quark interchange

  11. phase shift Experimental data of S-wave I=2 elastic phase shifts for  scattering in vacuum for are reproduced.

  12. unpolarized cross section

  13. transition amplitude in the prior form transition amplitude in the post form

  14. Buchmuller-Tye potential in vacuum Linear confinement and the potential arising from one gluon exchange plus perturbative one- and two-loop corrections W. Buchmuller, S.-H.H. Tye, Phys. Rev. D24 (1981) 132

  15. T=0.58Tc T=0.66Tc T=0.74Tc T=0.84Tc T=0.9Tc T=0.94Tc T=0.97Tc T=1.06Tc T=1.15Tc F. Karsch, et al., Nucl. Phys. B605, 579 (2001)

  16. Medium Effect Lattice QCD calculations give temperature-dependent quark-quark potential. Medium screening leads to weak binding of quarks. When temperature increases, the confinement potential gets weak and the bound state gets loose.

  17. central spin-independent andtemperature-dependent potential in medium critical temperature Tc=0.175 GeV. Y.-P. Zhang, X.-M. Xu, H.-J. Ge, Nucl. Phys. A 832 (2010) 112

  18. the parametrization fit to the lattice data

  19. spin-spin interaction arising from one gluon exchange plus perturbative one- and two-loop corrections by means of Foldy-Wouthuysen canonical transformation.

  20. meson masses at T=0 mass splittings experimental values m-m=0.6294 GeV 0.6304 GeV mK*-mK=0.39865 GeV 0.3963 GeV masses mJ/=3.13509 GeV 3.096916 GeV m´=3.69248 GeV 3.68609 GeV mc=3.50578 GeV 3.5253 GeV mD=1.90578 GeV 1.86722 GeV mD*=2.05274 GeV 2.00861 GeV

  21. meson masses from the Schrodinger equation with Vsi+Vss

  22. meson masses from the Schrodinger equation with Vsi+Vss

  23. charmonium dissociation Calculate the transition amplitudes, and , with the Fourier transform of thepotential Vsi+Vss to obtain unpolarized cross sections for 15 reactions

  24. parametrizations For endothermic reactions For exothermic reactions

  25. SUMMARY We have offered (1) a temperature-dependent quark potential; (2) temperature-dependent meson masses; (3) temperature-dependent cross sections for -charmonium and -charmonium dissociation reactions.