1 / 35

Quark models for meson

Quark models for meson. Jialun Ping, Chengrong Deng, Hongxia Huang, Fangfang Dong, Fan Wang Nanjing Normal University Nanjing University. Contents. Motivation Quark models for mseon Quark model for tetra-quark system Unquenched quark model Remarks. Motivation.

archie
Download Presentation

Quark models for meson

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Quark models for meson Jialun Ping, Chengrong Deng, Hongxia Huang, Fangfang Dong, Fan Wang Nanjing Normal University Nanjing University Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  2. Contents Motivation Quark models for mseon Quark model for tetra-quark system Unquenched quark model Remarks Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  3. Motivation Meson ( ) and baryon (qqq): open the gate for understanding QCD The unique color structure: advantage: makes model construction easier and effective disadvantage: minimizes the effect of color confinement Multi-quark systems: etc., with abundant color structures, provide more information on color confinement Since 2003, a lot of new hadron states: (BABAR, Belle, BES, CLEO, CDF,…) difficult to fit to the conventional picture of hadrons, multi-quark states? Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  4. qqqq qqqqq qqqqqq Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  5. Summary of the Charmonium-like XYZ states Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  6. Explanations: • Tetra-quark states • Molecules of conventional mesons • Hybrid states • …… • What are mesons? • Is the time for unquenched quark model coming? Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  7. Non-relativistic quark models Chiral quark model Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  8. Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  9. Quark model without σ-meson exchange same as chiral quark model, but without σ-meson exchange Experimental search of σ-meson PDG: ups and downs BES (2004): (541±39) – i (252±42) ππ S-wave resonance Nucl. Phys. A637(1998)395 Prog. Theo. Phys. 103(2000)351 Phys. Rev. C70(2004)014002 correlated 2π-exchange: strong repulsive core at short ranges moderate attraction at intermediate distances Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  10. Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  11. Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  12. Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  13. Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  14. Remarks Non-relativistic quark model can give a good description of meson spectrum. σ-meson exchange is not indispensable for meson spectrum. The single-Gaussian approximation, which is good for baryon spectrum, is too crude for meson spectrum. There are some meson states, mainly the scalar mesons, can not be well described in quark model, other configuration, four-quark states may be needed. E.g., the mass of σ-meson can be reproduced as a four-quark state, (Phys. Rev. D82(2010)074001.) Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  15. Quark model for tetra-quark states The results from Lattice：PRL 86(2001)18 hep-lat/0407001 hep-lat/0507187 Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  16. “Alternative constituent quark model” Conventional quark model The two-body confinement potential is replaced by T. Goldman and S. Yankielowicz, PRD 12(1975)2910: relativistic: linear non-relativistic: quadratic Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  17. The Confinement of tetra-quark Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  18. Jacobi ordinates As an example, taking Y(2175) as a tetrquark state: Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  19. Total wavefunction: Two channels: Orbital wavefunctions (Gaussian Eanpansion Method used): Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  20. Numerical results Energy Channel I: 2275MeV; Channel II: 2193MeV Channel coupling: 2178 MeV Naïve quark model: 2560 MeV Chiral quark model: 2400 MeV Spatial structure Similarly, for : 587 MeV and 1019 MeV. Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  21. New color structure Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  22. Zero-order approximation Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  23. Numerical results Single Channel calculation: Channel I: 2273 MeV; Channel II: 2216 MeV Channel coupling: 2196 MeV It has similar energy as other color structures. The coupling of different color structures is needed to account for the decay. It is difficult …… Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  24. 3P0 Model and Unquenched Quark Model 3P0 model: quark-pair creation (QPC) model quark pair: JPC=0++ L=1, S=1 Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  25. Transition operator wavefunction Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  26. Unquenched quark model wavefunction Hamiltonian Eigenequation Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  27. Mass equation Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  28. Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  29. B.Q.Li,C.Meng,K.T.Chao,PRD80(2009)014012 Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  30. mass shifts of charmonium states: (in MeV) Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  31. Parameters in unquenched quark model Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  32. Charmonium masses in unquenched quark model Preliminary results ! Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  33. D.Morel: nucl-th/0204028 (3+5 mixing) Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  34. Remarks Four-quark components have an rather large contribution to meson masses. Meson spectra should be re-constructed. 3P0 model needs to be modified. 2+4 mixing is also important for understanding tetraquark states It is time for unquenched quark model! Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

  35. Thanks for your attention! Hadron Nuclear Physics 2011, APTCP, Pohang, Korea

More Related