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Exploring Hybrid and Exotic Particle Candidates from B Factories

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67 diapositives · 813 Views · Sep 20, 2014

This talk by Tom Browder from the University of Hawaii delves into discoveries from BaBar, Belle, CLEO, CDF, and D0 experiments. Insights from Perkins' "Introduction to High Energy Physics" are explored, focusing on new particle phenomena like X and Y states. The discussion examines the possibility of 4-quark or quark-antiquark-glue combinations, proposing unconventional theories challenging standard particle physics. Unique charmonium states, such as X(3940) and Y(3940), offer intriguing avenues for exploration. B-factories serve as hubs for investigating cc production mechanisms, shedding light on exclusive B decays. The lecture tackles the complexities of observed states and unanticipated particle behaviors, expanding the frontiers of high-energy physics.

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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