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Charmonium Results from CLEO Collaboration: Aug 18, 2004

This report outlines the motivation behind studying charmonium, including better understanding of QCD, testing ground for future physics, and heavy quarkonia properties. Results from CLEO collaboration regarding various charmonium states (ψ(2S), ηc, ηc', X(3872)) branching fractions, masses, and transitions are presented. Photon spectrum analysis, event characteristics, and distinguishing γγ fusion from ISR are discussed. Final results and interpretations are provided, showing limits on X(3872) properties. The study sheds light on charmonium dynamics and implications for particle physics.

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Charmonium Results from CLEO Collaboration: Aug 18, 2004

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  1. Charmonium Results from CLEO Y. Kubota representing the CLEO collaboration 18 Aug 2004

  2. Outline • Motivation • (2S)cJ branching fractions • c(’) masses and (2S)c branching fractions • X(3872) search (preliminary) CLEOc Charmoium results

  3. Motivation • Better understanding of QCD • Needed for better measurements of electroweak processes • Good testing ground of LQCD • Good practice to understand future physics, which involves strong coupling (Lepage) • Heavy quarkonia • relativistic effects are smaller CLEOc Charmoium results

  4. cJ • cJ: • well established. • E1 transitions from (2S) (transition rates) •  fusion production (Γγγ’s) • pp annihilation (masses, widths) CLEOc Charmoium results

  5. c(’) • c: • well established. • M1 transition from J/ & (2S) (mass, transition rates) •  fusion production (mass, width, Γγγ’s) • pp annihilation (mass, width) • c’: • Established two years ago by Belle (B decays, etc.), and CLEO and Babar ( fusion production) • Crystal Ball result using M1 transition from (2S) is most likely false. CLEOc Charmoium results

  6. Photon Spectrum (2.7 pb-1) • No 0 suppression • cos >0.5 – used in analysis • Max 0 suppression CLEOc Charmoium results

  7. cFit results MIP Solid: Signal+background Dotted: generic background only Dashed: generic + MIP background Background subtracted Systematic errors: Event selection, Fitting, 0 suppression J/c 10000 0 CLEOc Charmoium results

  8. (2S)cJBranching Fractions • CLEOc & C-Ball agree well. • Ratios of BF’s very close to 1 • within 3-8% systematic errors • NRQCD expectations ~ (2J+1)Eγ3 • Relativistic effects important? CLEOc Charmoium results

  9. cFit results Solid: Signal+backgroundDotted: generic background onlyBackground subtracted CLEOc Charmoium results

  10. c mass and (2S)c BF • mc = (2970±7) MeV • Consistent w/ world average of ~2980 MeV. • B((2S)c) = (0.32±0.04±0.06)% • Sensitive to relativistic corrections. • Crystal Ball obtained (0.28±0.06)% for Γc = (11.5±4.5)MeV. • CLEOc would have given (0.25±0.06)% for this Γc – entirely consistent. • About expected level by theories. CLEOc Charmoium results

  11. (2S)c(2S) • No trace of this transition at Eγ = 91 MeV • BF < 0.2% at 90% C.L. • C-Ball presented BF ~ (0.2-1.3)% with 95% C.L. • Given the mass & width of c(2S) of 3638 and 25 MeV at recent experiments (Belle, CLEO, Babar), we expect Eγ = 47 MeV and width ~ 10 MeV • No meaningful sensitivity exists at this energy and width. CLEOc Charmoium results

  12. X(3872): background • Found by Belle in B decays • Confirmed by CDF and D0 – general hadronization • Mass = 3872 MeV • Width – smaller than resolution ~ 2 MeV • Decays to π+π–J/ψ; no report on π0π0J/ψ • Has not been found in γχ, γJ/ψ, DD, D0D0π0 CLEOc Charmoium results

  13. What is X(3872)? • Charmonium? • From narrow width, • 13D2(2– –), 13D3(3– –), 21P1(1+–) all C = –, or • 11D2(2–+), 23P1(1++) all C = + • DD* molecule? • Close to DD* threshold and from lack of π0π0J/ψ decays • ρ0J/ψ decay? • Then X(3872) will most likely be 0–+ or 1++. • Glueball? • Three-gluon glueball of 1– – at m = 3850 MeV predicted. CLEOc Charmoium results

  14. JPC determination • It will be useful to know what JPC of X(3872) is. • BES showed that its production in ISR (e+e–γe+e–γX(3872) is invisible (ECM = 4 GeV) • Γee×B(π+π–J/ψ) < 10 eV (90% C.L.) • JPC1– –? • CLEO seeks X(3872) in 15 fb-1 of data using • γγ fusion (C = + & J = evenonly) • ISR (ECM = 10 GeV) CLEOc Charmoium results

  15. Event characteristics • Missing momentum/energy in the beam directions • In γγ fusion, missing momentum ~ 0 • In ISR, missing momentum ~ missing energy • Missing momentum perpendicular to the beam is small • 4 charged particles • No neutral energy CLEOc Charmoium results

  16. Result • Clear peak for ψ(2S) • No event for X(3872) CLEOc Charmoium results

  17. Distinguishing γγ fusion from ISR • Due to the difference in the beam-direction motion of X(3872) candidates, we can distinguish the two production mechanism. ISR γγ fusion CLEOc Charmoium results

  18. Final results • (2J+1)Γγγ×B(Xπ+π–J/ψ) < 12.9 eV (90% C.L.) • Γee×B(π+π–J/ψ) < 8.0 eV (90% C.L.) CLEOc Charmoium results

  19. Interpreting results • (2J+1)Γγγ×B(Xπ+π–J/ψ) < 12.9 eV • Assume B(BKX) ~ B(BKψ(2S))  • B(Xπ+π–J/ψ) = 2%  • (2J+1)Γγγ < 0.6 keV • Compare it to (2J+1)Γγγ for ηc, χc0, and χc2. • 7.4 keV (ηc); 2.6 keV (χc0); 2.6 keV (χc2) • Γee×B(Xπ+π–J/ψ) < 8.0 eV (90% C.L.) • This is less than 1% of ψ(2S) production in ISR events. CLEOc Charmoium results

  20. Summary • Precise measurements of rates for • (2S)cJ and • (2S)c • Limit on (2S)c(2S) • Upper limits on X(3872) productions in • ISR • γγ fusion CLEOc Charmoium results

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