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Charmonia above open charm threshold

Charmonia above open charm threshold. Yu.S.Kalashnikova ITEP. Charmonium. m c = 1.5 GeV. Theory: Godfrey- Isgur. M, MeV. 4250. Expected. 4000. ?. ?. 3750. DD. 3500. 3250. 3000. 0 -+. 1 --. 0 ++. 1 ++. 2 ++. 1 +-. 2 --. 3 --. 2 -+.

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Charmonia above open charm threshold

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  1. Charmonia above open charm threshold Yu.S.Kalashnikova ITEP

  2. Charmonium mc = 1.5 GeV Yu.S.Kalashnikova, ITEP

  3. Theory: Godfrey-Isgur M, MeV 4250 Expected 4000 ? ? 3750 DD 3500 3250 3000 0-+ 1-- 0++ 1++ 2++ 1+- 2-- 3-- 2-+ Yu.S.Kalashnikova, ITEP

  4. All eight cc states below DD threshold are well-established, and properties are compatible with quark model New states above DD threshold do not fit quark-antiquarkassignement New degress of freedom enter the game Yu.S.Kalashnikova, ITEP

  5. New charmonia Yu.S.Kalashnikova, ITEP

  6. Warning: • Most of the new states are found only at • B-factories • The number of events is tiny • Not all the states seen at Belle are confirmed • by BaBar, and vise versa Yu.S.Kalashnikova, ITEP

  7. Degrees of frreedom which are frozen in quark models start to reveal themselves • Hybrid excitations • DD loops and threshold • effects • Pions Yu.S.Kalashnikova, ITEP

  8. I. HYBRIDS Yu.S.Kalashnikova, ITEP

  9. Hybrid excitations:gluon with two “minimal” strings attached Yu.S.Kalashnikova, ITEP

  10. Y(4260): hybrid charmonium? BaBar Belle Yu.S.Kalashnikova, ITEP

  11. Y(4320): hybridcharmonium? Yu.S.Kalashnikova, ITEP

  12. Charmonium hybrids(mass, MeV) Exotics! QCD string: Yu.S.K., A.Nefediev Lattice: J.Dudeket al Yu.S.Kalashnikova, ITEP

  13. Selection rule: D(*)D(*) hmagnetic D(*)DJ(*) Yu.S.Kalashnikova, ITEP

  14. Y(4260) and Y(4320) as hybrids: • Observed in ISR, so they are vectors • e+e- width is small • reside in a dip in R • do not couple to D(*)D(*) hybrids? • LGT: (1--)h @ 4400 MeV • Scc = 0 for (1--)h -> spin flip is needed • for J/ mode Problems: Yu.S.Kalashnikova, ITEP

  15. II. LOOPS Yu.S.Kalashnikova, ITEP

  16. DD loops:(unquenching quark model) D D = D D D D D D D cc cc + D D D D D Yu.S.Kalashnikova, ITEP

  17. Coupled channels cc DD p Interaction: f(p)= One bare cc state with the mass M0 Hadronic shift

  18. Quark models provide a good fit to lowest charmonia levels and 1D, 3S, 4S excitations With loops included, in explicit calculations one finds large hadronic shifts (about 200 MeV from the lowest set of thresholds only) Does unquenching destroy naïve quark model? Yu.S.Kalashnikova, ITEP

  19. Sum rules: (exact in nonrelativistic limit) • Hadronic shifts are the same • for a given multiplet • There is no JLS  JL’S’ mixing • via loops Loop effects are hidden? Yu.S.Kalashnikova, ITEP

  20. Sum rules are severely violated by S-wave thresholds strongly coupled to the initial qq state: • Nonanalyticity of the DD scattering amplitude, • and cusps in crossection • Extra singularities (CC poles) In the Nc  limit genuine quarkoniumsurvuves, but CC state disappears Yu.S.Kalashnikova, ITEP

  21. Weird charmoniaand relevant thresholds D0D0*3872 MeV D+D-*3879 MeV • X(3872) • Y(4260) DD14285 MeV • Y(4325) D*D04360 MeV • (4430) D*D14430 MeV Threshold affinity means that the admixture of D-meson pairs in the wavefunction could be large Yu.S.Kalashnikova, ITEP

  22. X(3872) 37 evt 10 X(3872) 25 evt 3.5 σ MJ/ψππ– MJ/ψ MX = 3872.0 ±0.6 ± 0.5 MeV3873.4 ±0.14 MeV Br(B-→ XK-)×Br(X→J/ψππ) = (1.3 ± 0.3) 10–5 (1.28± 0.41) 10–5 3871.77 522 evt 5.2σ 659 evt 11.6σ MX = 3871.3 ±0.7 ± 0.4 MeVMJ/ψππ–MJ/ψ = 774.9 ±

  23. Yu.S.Kalashnikova, ITEP

  24. M(D0D*0)=3871.81  0.36 MeVM(X)=3871.46  0.09 MeVJPC = 1++ X(3872) as a CC state: bare c1(23P1) charmonium state attracted to D0D*0 S-wave threshold Bugg, YuSK, Danilkin&Simonov Yu.S.Kalashnikova, ITEP

  25. Spectral density of the 23P1charmoniumlevel in the cc-D(*)D(*) coupling scheme YuSK Danilkin&Simonov Quark model for bare state + 3P0-type pair creation vertex Yu.S.Kalashnikova, ITEP

  26. Flattè analysis of Belle data on X YuSK&Nefediev D0D00 J/ Assumptions: Coupled-channel model for the X Conclusions: Belle data are compatible with this assumption Yu.S.Kalashnikova, ITEP

  27. III.OPE –BOUNDMOLECULES Yu.S.Kalashnikova, ITEP

  28. Mesonic molecules bound by one pion exchange One pion t-channel exchange in the I=0 1++ DD* channel is attractive, so a molecule can be formed, in perfect analogy with deuteron Voloshin@Okun, deRujula, Georgi&Glashow (circa 1976) Tornqvist, Swanson,… Yu.S.Kalashnikova, ITEP

  29. Star flipping:OPE in the 1++ DD* D* D  D* D X(3872) as DD* bound-state Yu.S.Kalashnikova, ITEP

  30. Deeply bound molecular states DD* : generic vertex is D* -> D in P-wave, molecule is loosely bound D(*)DJ: generic vertex is DJ -> D(*) in S-wave, molecule is deeply bound Y(4260) and Y(4320) as 1S and 2S molecular states in the D*D1 system bound by one pion exchange Close et al Yu.S.Kalashnikova, ITEP

  31. However… In existing molecular models pions are not treated dynamically, but enter static potential Three-body cuts are ignored Inclusion of dynamical pions leads to imaginary part of the potential, and bound states cease to exist Baruet al Yu.S.Kalashnikova, ITEP

  32. IV. Z+s Yu.S.Kalashnikova, ITEP

  33. Yu.S.Kalashnikova, ITEP

  34. Yu.S.Kalashnikova, ITEP

  35. Z-states are charged, and, as such, are necessarily exotic Z-states are seen only @ Belle • If exist, could be • compact tetraquarks • molecules • hadrocharmonia(whatever it means) Yu.S.Kalashnikova, ITEP

  36. Conclusions • There is no theoretical concensus on the • nature of new states • More high statistics and high resolution • data is needed to confirm/rule out • different assignements Yu.S.Kalashnikova, ITEP

  37. PANDA on the horizon: pp -> cc pp -> cc + light hadrons • High luminosity  O(103) cc pairs per day • High beam momentum resolution  precise • measurements of mass and width • Detector  hadronic modes accessible • (DD, DD etc) Yu.S.Kalashnikova, ITEP

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