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Candidates for Hybrids and Exotics from the B Factories

Candidates for Hybrids and Exotics from the B Factories. Tom Browder (University of Hawaii). Will discuss results from BaBar, Belle, CLEO, CDF and D0 in this talk. [Thanks to S. Olsen, B. Yabsley (Belle) and J. Olsen (BaBar)]. Textbook of Perkins, Introduction to High Energy Physics p.118.

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Candidates for Hybrids and Exotics from the B Factories

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  1. Candidates for Hybrids and Exotics from the B Factories Tom Browder (University of Hawaii) Will discuss results from BaBar, Belle, CLEO, CDF and D0 in this talk. [Thanks to S. Olsen, B. Yabsley (Belle) and J. Olsen (BaBar)] Textbook of Perkins, Introduction to High Energy Physics p.118 “The states observed in nature consist of three-quark combinations (the baryons) and quark-antiquark combinations (the mesons).” Yes, but other possibilities such as 4-quark or quark-antiquark-glue combinations are not forbidden by any conservation law.

  2. Unexpected New Particles: (X and Y) eeY(4260) (2S) eeY(4324) e+ e-J/ X(3940) Y(3940)J/ X(3872)J/ Six new charmonium states were found above DD threshold (incl Z) Most of these heavy charmonium-like states were not anticipated by theory Are any of these new states 4-quark combinations or hybrids ?

  3. Charmonium is a good place to look for non-q qbar mesons: A new q qbar meson decaying to c cbar has to fit into these slots:

  4. X and Y particles • X(3940) • e+e-J/y X & e+e-  J/y DD* • X(3872) • p+p- J/y in BKp+p-J/y • Y(3940) • wJ/y in BK wJ/y • Y(4260) • p+p-J/y in e+e-g p+p- J/y • Y(4324) • p+p-y’ in e+e-g p+p-y’ Are these all conventional charmonium states ?

  5. B-factories are Charmonium factories cc production mechanisms @ a B factory: • B meson decays • e+e- annihilation • gg collisions • e+e- radiative return (ISR)

  6. cc production in B decays J = 0 or 1 j=½ j=½ Spectator model suggests Jcc= 0 or 1 should dominate exclusive BK(cc) decays.

  7. Allowed decays all have BF’s~10-3from PDG2004 hcK 0.9 x10-3 J/yK 1.0 x10-3 J/yK* 1.4 x10-3 J/yK12701.8 x10-3 y’K 0.7 x10-3 y’K* 0.9 x10-3 cc0K 0.6 x10-3 cc1K 0.7 x10-3 Note that BK cc(J=2) still not seen

  8. Mechanism: e+e- J/ψ + (cc) J/y hc’ cc0 hc X X (almost) always contains (cc) C(X) = +1 M(X) consistent with bkg e.g. J/ψJ/ψ is forbidden

  9. gg DD JPC = 0++, 2++ e+e- g (cc) ISR cc JPC = 1--

  10. 1st state to be discussed today:e+e- J/yX(3940) for e+e-J/y + X hep-ex 0507019, K. Abe et al, (Belle collab). PRL 98, 082001 (2007)

  11. X(3940)D*D is strong(N.B.DD & wJ/y not seen) Only one D is fully reconstructed B(DD)<41% J.Rosner: hep-ph/0609195 Since the X(3940) recoils against J/ψ it has J=0. Since it decays to D D* but not to D Dbar, it is probably the ηc(3S) rather than the χc0’ B(D*D)>45% consistent with 100% From X(3940) → D*D: M = (3943 ± 6 ± 6) MeV G = (15.4  10.1) MeV G < 52 MeV at 90%CL K. Abe et al, (Belle collab). PRL 98, 082001 (2007)

  12. Is the X(3940) the hc”? M= 3943 MeV is ~150 MeV low Γ<52 MeV too narrow? 3940 Other more exotic possibilities to be mentioned by F. Close

  13. X(3872) in BKp+p-J/y y’p+p-J/y s 2.9 MeV X(3872)p+p-J/y M(J/ψ)- M(J/ψ) S. K. Choi et al, PRL 91, 262001

  14. X(3872) is also seen in p pbar X(3872) D0 CDF 11.6s X(3872) PRL 93, 072004 (2004) PRL 93, 162002 (2004) Production properties similar to those of the ψ’

  15. C=+1 assignment for the X(3872) is established by a variety of modes A small signal for X(3872) γJ/ψ seen in: Belle hep-ex/0505037 & Expect radiative mode is dominant for a normal charmonium state X(3872)”w”J/y seen Belle E. Swanson, hep-ph/0311229 PLB 588, 189 (2004) hep-ex/0505037

  16. C=+1 assignment for the X(3872) (cont’d) M(pp) looks like a r CDF PRL 96 102002 (2006) Belle

  17. X(3872) has no satisfactory cc assignment 3872 cc1’ Br(gJ/y) too small & Br(rJ/y) too large hc2 • hc2rJ/y isospin forbidden • BKcc(J=2) suppressed

  18. What is the X(3872) ? The mass, width and decay modes do not appear to correspond to those of any predicted charmonium state. One possibility suggested by a number of authors is a loosely bound S-wave molecule of charm mesons. F. Close, P.R. Page, Phys. Lett. B 578, 119 (2003) N.. A. Tornqvist, Phys Lett. B 590, 209(2004) E. Braaten, M. Kusunoki, S. Nussinov, Phy. Rev. Lett. 93, 162001 (2004) Another intriguing idea: X(3872)= c cbar u ubar state. In such a 4-quark picture there should be two neutral states, X0, c cbar u ubar, c cbar d dbar as well as charged states, X +, c cbar u dbar, c cbar d ubar etc…. L. Maiani, F. Piccinini, A. D. Polosa, V. Riquer, Phys Rev. D71: 014028 (2005)

  19. X mass is near the D0D*0 threshold PDG MX3872: 3871.2 ± 0.5 MeV PDG06: mD0+ mD*0 = 3871.1 ± 0.8 MeV Use CLEO hep-ex/0701016 3871.7 ± 0.4 MeV Average for threshold: 3871.6 ± 0.4 MeV D*0D0 ”binding energy” = 0.4 ± 0.6 MeV

  20. ereJ/y k(erxeJ/y) 0++ 0-+ Ruled out by Belle qlp y c2/dof=34/9 c2/dof = 34/9 |cosq| |cosqlp| |cosy| rule out 0++ & 0 -+

  21. Belle Angular Analysis of X(3872) 1++ assignment consistent with data

  22. X(3872) angular analysis from CDF Check χ2 1++ or 2-+ A.Abulencia et al, CDF, hep-ex/0612053, PRL 96, 102002 (2006).

  23. If the X(3872) is a D0 D*0 molecular resonance with ωJ/ψ and ρJ/ψ in its wavefunctions, then expect decays to D0 D0 0and D0 D0 γ E.S. Swanson, Phys. Lett, B588 189(2004) Also see M. B. Voloshin, Phys. Lett. B579, 316 (2004)

  24. Belle: Threshold peak in BK (D0D00) Belle hep-ex/0606055  published in PRL M(DDp) DE +0.3 -1.6 M=3875.4  0.7  0.8 MeV Br(BKX)Bf(XD0D0p0 ) = (1.27  0.31 )x10-4 +0.22 -0.39 Br(XD0D0p0) Br(Xp+p-J/y) ~ 9

  25. BaBar @Moriond 2007 Threshold enhancement in B(D0 D*0) K The mass is also 2.5σ above the nominal X(3872) mass (puzzling…is this the same beast ?)

  26. Threshold enhancement in B(D0 D*0) K BaBar 2007 Hints of signals are seen in both B+ and B0 modes

  27. X(3872) has no satisfactory cc assignment 3872 cc1’ Br(gJ/y) too small & Br(rJ/y) too large hc2 • hc2rJ/y ispin forbidden • D0D0p0 @ thresh. suppressed • BKcc(J=2) suppressed

  28. Comments on the D0D00 mass peak PDG MX3872: 3871.2  0.5 MeV ~2s discrepancy  2xPDG06 error on mD0 (could be  2.0 MeV) +0.3 -1.6 Fitted M: 3875.4  0.7  0.8 MeV DD* “Binding Energy?”: Here error on mD0 drops out +0.3 -1.6 M–(mD0+ mD*0) = +4.3  0.7 MeV Caution: nominally ~2.3sabove D0D*0 threshold (but errors are non-Gaussian)

  29. Braaten et al: XD D*0 mass spectrum Theoretical prediction for a loosely bound D D* state.

  30. Signals for X(3872) in B0 and B+ modes B. Yabsley Important to confirm with higher statistics.

  31. BaBar looked for a charged partner of the X(3872) and excluded isospin 1: BF(B0X- K+ ) BF(X  J/ψ-0) < 5.4 x 10-6 BF(B- X- K0 ) BF(X  J/ψ-0) < 2.2 x 10-5 c.f BF(B0X0 K+ ) BF(X 0 J/ψ-- +) =(1.28  0.41 ) x 10-5

  32. Next State: Y(3940) in BK ω J/ψ Reconstruct, BK ω J/ψ. Cut on K ω mass to remove contributions from K** resonances. M≈3940 ± 11 MeV G≈ 92 ± 24 MeV G(Y3940 wJ/y)> 7 MeV (an SUF(3) violating decay) ~ this is 103 x G(y’  hJ/y) (another SUF(3) violating decay) If the Z(3930) is the χc2’ the Y(3940) mass is too high for it to be the χc1’ M(wJ/y) MeV S. K Choi et al, (Belle) PRL94, 182002 (2005) Rosner: However, χb1,2’ states are seen to decay to ωΥ(1S)

  33. Is there a cc slot for the Y(3940) ? hc” Mass is low cc1’ Can M(cc1’)>M(cc2’)? 3940 3931 cc0’ “ “ “ “ Might be a hybrid but the mass is too low. Hybrids expected at 4300-4500 MeV.

  34. 233 fb-1 e+e- γisrY(4260) at BaBar BaBar PRL95, 142001 (2005) Not seen in e+e- hadrons X.H. Mo et al, hep-ex/0603024 Y(4260) ~50pb 4260 ~3nb BES data s(e+e-+p-J/)~50pb G(Y4260p+p- J/y) > 1.6 MeV @ 90% CL 4260 (there is a dip here !)

  35. 13.3 fb-1 Y(4260) at CLEO-III ISR (1S)-(4S) 13.3 fb-1 Consistent results MeV MeV T.E. Coan et al., PRL 96, 162003 (2006) CLEO PRD 74 091104 (2006)

  36. Confirmation of Y(4260) in ISR at Belle M(+ - ) For y’p+p-J/y in the same dataset: M(y’) = 3685.3  0.1 MeV (PDG: M(y’)=3686.09  0.04)

  37. Y(4260) at BaBar / CLEO / Belle Roughly consistent, within ~2.5s -4.2 -3 -6 -16 -6 -4 -25 GeeB(p+p-J/y)(eV)

  38. No 1-- cc slot for the Y(4260) X.H. Mo et al, hep-ex/0603024 PLB 640, 182 (2006) 4260 4280

  39. s(e+e- DD) using ISR BaBar hep-ex/0607083

  40. s(e+e-D*D(*))@ s 4 GeV Belle: ISR + Partial Reconstruction hep/ex0608018, to appear in PRL detected D(*)+ p- D*- D0 Mrec(gpD(*)) –Mrec(gD(*)) Undetected (but constrained)

  41. results: y(4040) y(4160) y(4415) Belle s(e+e- D*+D*-) y(4260) s(e+e- D+D*-)

  42. D2D The Y(4324) structure from BaBar e+e-gISR (p+p-y’) 298fb-1: hep-ex/0610057 Nevt = 68 (<5.7 GeV/c2) Nbkg = 3.1 1.0 M=4324  24 MeV G = 172  33 MeV above all D**D thresholds Not compatible with the Y(4260) Incompatiblewith (4415), nor is it well described by the Y(4260) A single resonance can describe the structure (<5.7 GeV/c2) well mass=(432424) MeV/c2, =(17233) MeV (statistical errors only)

  43. Another new structure (φ f0 ) in ISR found by BaBar (hep-ex/0610018) Is this the s sbar analogue of the Y(4260) ?

  44. New Particle Summary+Guesses • X(3940) (e+e- J/y X) • C=+1 • Might be the hc” • X(3872): • JPC = 1++ • Br(Xp+p-J/y) large • Br(XD0D0p0) seen; ~ 9xBr(Xp+p-J/y) D*D A 4-quark or D D*0 molecule candidate

  45. 233 fb-1 • Y(3940)wJ/y • G( Y3940 wJ/y)>7 MeV (large!) • “Y(4260)”p+p-J/y • G(y4260p+p-J/y)>1.6 MeV • JPC=1--, not seen in e+e- hadrons • no obvious D**D threshold distortions • “Y(4324)”p+p-y’ • above allD**D thresholds summary cont’d But other properties compatible with a radially excited χc1,2 state A good c cbar hybrid candidate

  46. Personal Conclusions (Not endorsed by the management of any experiment.) • Two intriguing exotic candidates: the X(3872) and the Y(4260). • Additional measurements of more modes and with higher statistics will clarify the interpretation of the above two states. • It is important to confirm the X(3940), Y(3940) and Y(4324) states and learn more about them. • Frank Close will discuss the interpretation in greater depth with a stronger dose of theory.

  47. Back-up slides

  48. BaBar: e+e-gISR (p+p-y’) Efficiency is changing rapidly near threshold

  49. DD** threshold in relation to the “Y(4260)” D2D D** spectrum D1D No obvious distortions 4.28-mD M(p+p-J/y) GeV

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