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The Y(4260) at CLEO

The Y(4260) at CLEO. Y(4260) Discovery at BABAR Y(4260) in ISR from s=10 GeV Preliminary Direct e + e - X J/ in charmonium region: Y(4260) Coan et al., PRL 96 (2006) 162003. Status of Y(4260)Open Charm Conclusions. Ian Shipsey Purdue University For the CLEO Collaboration.

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The Y(4260) at CLEO

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  1. The Y(4260) at CLEO • Y(4260) Discovery at BABAR • Y(4260) in ISR from s=10 GeV Preliminary • Direct e+e-X J/ in charmonium region: Y(4260) Coan et al., PRL 96 (2006) 162003. • Status of Y(4260)Open Charm • Conclusions Ian Shipsey Purdue University For the CLEO Collaboration I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06

  2. Y(4260) Discovery BABAR PRL 95, 142001 (2005) • e+e-→ISRY(4260), Y(4260)+-J/  JPC=1- - • At a minimum in s(e+e-→hadrons) • Why hasn’t this been seen before?s(e+e-J/ypp)  50 pb-1 at 4.26 GeV(based on ISR rate at BaBar)R~0.05<<Error ons(e+ehadrons) • June 06,Belle also see the state at a 2.5sigma (35 MeV) higher mass than BaBar,&larger width(Olsen, QWG2006) 233 fb-1 I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06

  3. CLEO & Y(4260) In 2005: • BaBar observation of Y(4260) added another perplexing state to the charm region • Proposed explanations mostly unconventional • Y(4260) needed confirmation, • Arguably most intriguing of XYZ’s, hybrid candidate? • 1-- state: can be directly produced in e+e- • Two-pronged approach: • Confirm/refute BaBar with RR’s from s=10 GeV Y(1S,2S,3S,4S) (CLEO III) • Direct production at s=4.26 GeV (CLEO-c) • If confirmed, goal: limit theory explanations by measuring the pattern of decay modes I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06

  4. Like BaBar, search for/study Y(4260) production in ISR 13.3 fb-1 of CLEO III Y(nS) data Reconstruct ee and µµ decays of the J/ψ Select ISR events by plotting the missing mass squared of the J/ψππ system CLEO Y(4260) in ISR @s=10 GeV (2S) (2S) Missing Mass2 (GeV2) I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06

  5. CLEO Y(4260) in ISR @s=10 GeV M() (GeV) • binned likelihood fit to single Breit-Wigner convoluted with MC determined resolution & linear background CLEO Preliminary NEW Y(4260) Note very low bgd: hermeticity in the c.m. CLEO Preliminary 4.9σ significance M Γ dominant syst: cut variations M() consistent w/S-wave, no structure, This & ISR production verifies vector nature of state I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06

  6. Comparison to other experiments CLEO Preliminary Y(4260) BABAR-Belle differ by 2.6 sigma for mass but bracket CLEO BABAR Belle Preliminary Single resonance describes data well CLEO consistent with both BaBar & Belle I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06

  7. Observed & Predicted Spectra of Charmonium States 4S ? Y(4260) ? 3S No 1– cc slot for the Y(4260) 2S 1S I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06

  8. DD** threshold & the “Y(4260)” D** spectrum Single resonance describes data well 4.28-mD CLEO Preliminary M(p+p-J/y) GeV I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06

  9. Direct Production @ s=4260 …may prove crtical to reveal the nature of the 4260 Very wide range of decay mode (16) examined @CLEOc Modes: • +- J/ • 00 J/ •  J/ • K+K- J/ • 0 J/ • ’ J/ • +-0 J/ • +- (2S) •  (2S) • +-  Using the following intermediate decays: • J/+-, e+e- • , +-0 • ’ +-, +- • (2S) +-, e+e-, +-J/ • K+K- • Suite of channels motivated by the proposed theoretical scenarios. • Open charm modes crucial & in progress I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06

  10. The CLEO-c Scan Dataset 4170 Luminosity 3770 4260 317K decays 93K decays 1.8M decays Arbitrary Normalization I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06

  11. Build on previous analysis RR’s to y(2S) peak Direct decay (2S) Tail k, Missing Momentum (MeV) RR’s to y(2S) peak Direct decay (2S) Tail k, Missing Momentum (MeV) Recall (3770)XJ/: • Plot k=missing momentum (radiative photon energy) • Small signal at k=0 [direct y(3770) decay] • Huge peak corresponding to (2S), (2S)  XJ/ (radiative return, “RR”) • Direct & RR’s very well separated • RR leaks into the k=0 region • #RR’s  ee[(2S)] : predictable Adam et al., PRL 96 (2006) 082004 I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06

  12. Y(4260) direct: Large k: e+e- (2S) Theoretical RR-to-(2S) cross section 3770 anchor point: ee[(2S)] Agreement within 3% stat error: We understand our selection, efficiencies, & normalizations I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06

  13. Now focus on k0 ~35 net evt 11 CLEO s=4260 data ~7.7 net evt 5.1 • Almost pure signal • Confirms Y(4260) ISR analyses • CLEO adds 00J/, & K+K- J/ 3 net evt 3.7 Backgrounds from J/ sidebands & RR’s to (2S) tail near k=0 are small! All other final states examined produce ULs I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06

  14. Results@s=4260 MeV +- :<0.102 BaBar (prelim: hep-ex/0605086) I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06

  15. J/ cross sections Expected from BaBar result PRD73 (2006) 012005 (3770) signal (4040) signal? Entire signal @4160 consistent with tail of Y(4260) Y(4260) signals I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06

  16.  Mass Spectrum s=4260 MeVData MC • Plot shown is efficiency-corrected • No f0(980) or f0(600) [] • Slightly softer than (2S)-like MC spectrum • Data: disfavors Y(4260) as oddball (3g glueball) [ big  rate]. (4S) 3S = y(4040) should have a large +-J/ partial width cJ 0 molecule (no decay into 00J/) or baryonium(tiny KK J/) • Hyrbid and tetraquark remain possibilties  open charm I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06

  17. Open Charm@4260 • Hybrid charmonium  YD1D, D1’ D(D*) D • 2-body open charm decomposition crucial to finding a D1D enhancement from Y(4260) hybid • DsDs tetraquark • Total charm cross section at 4260  4 nb • But +-J/ is  50pb • Need to understand open charm decomposition at ~1% leval • Difficult to distinguish from multibody production, e.g. D*D, D*D* ! Tools: P(D0), angles, lower s? Total Hadronic Cross Section Sum of 2-Body Exclusive D(*)D(*) s (GeV) D1D ? D*D D*D* D*D D*D* D0D0 D0 Momentum (GeV/c) I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06

  18. Conclusions • 4.9 evidence for Y(4260)+-J/ in ISR from s=10 GeV data: M,  consistent w/BaBar & Belle • Direct e+e-Y(4260) studies @ s=4260 MeV • Signals: +- J/ (11), 00 J/ (5.1), & K+K- J/ (3.7) • (+-J/)  BaBar expectation • M() shows no structure [ no f0(980) or f0(600) ] • B[(4040) +- J/]<0.4% & B[ (4160) +- J/ ]<0.4% • Limits placed on 12 other charmonium decay modes & +-  • Data provides no support for Y(4260) as glueball, (4S), cJ 0 molecule, or baryonium • Hybrid interpretation has not been excluded • Y(4260)open charm under study: a challenging analysis There is a new spectroscopy in the 4 GeV energy region- together with precision D CKM physics (decay constants and form factors) and searches for new physics in DCPV, Dmix and Drare the new charm spectroscopy is one more reason why charm is important again I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06

  19. Backup Slides I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06

  20. Observed & Predicted Spectra of Charmonium States ? ? ! Y(4260) V(r)~log r Rosner & Quigg,Phys.Lett.B71:153,1977 I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06

  21. No 1-- cc slot for the Y(4260) X.H. Mo et al, hep-ex/0603024 4280 4280 I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06

  22. Datasets I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06

  23. Selection & Backgrounds • J/l+l-: e &  ID, bremm recovery, ~3 dilepton mass cut • Require event missing momentum consistent with zero within ~2.5 • No missing particles! • Background: e+e- J/ with  conversion • Require M()>400 MeV • e+e- (2S)  J/ • Calibrate rate with radiative returns to peak of (2S) Breit-Wigner • Will occur at a fixed missing momentum at each Ecm • Tail of (2S) Breit-Wigner: (2S) J/ (no missing mom) • Looks just like signal, dead-reckon with theoretical calculation • e+e- , KK, eeee, ee, ee • Will satisfy kinematics! (Corollary: Will do so for any “M(J/y)”.) • Subtract statistically with WIDER “Fake M(J/) Sidebands” around 2.9 & 3.3 GeV instead of 3.097 GeV • 20x size of +- window • ~5x size of 00 window • 30x size of K+K- window • 12x size of  window • Naïve scaling by window size cross-checked by counting yields in signal and sideband windows in background MC I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06

  24. KK J/ • Kinematically allowed for Ecm>4085 • Babar sees no signal Our selection requires at least one of kaon candidates to have p=0.2-0.5 GeV/c & Kaon ID consistency @<3. All 3 of our events have BOTH kaons id’d. 2 events in the 30x sidebands: 3 evt, 0.07 bgd: 3.7 significance MC prediction for K/ separation using dE/dx K/ Separation (#) I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06

  25. Systematics • Sources: • tracking, lepton ID, particle ID, mass window cuts, k window cuts: conservative estimates lead to 5-10% in all modes • Background subtraction: • gy(2S) ~5% • Fake J/y subtraction (sidebands): smaller than gy(2S • Statistical errors:16% (p+p-J/y at 4260) or larger I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06

  26. Other Features 00J/ I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06

  27. What’s known R Ecm 4.26 • BaBar observed 8 effect in radiative returns e+e-  Y(4260)   +- J/ AND 3.1 in B-K- Y(4260)  K- +- J/ • 50-90 MeV wide, 1 or several peaks • Predict 50 pb cross section for direct e+e- Y(4260) • No signal in two-photon production • No official comment from Belle 3.1 BKY(4260) 8 Aubert et al., PRL 95 (2005) 142001. I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06

  28. Theory (see Eichten talk & others to come) • How to create enhancement & simultaneously suppress of open charm ? • Lengthy papers, which include review Eichten, Lane, & Quigg, PRD 73 (2006) 014014; Swanson, hep-ph/0601110 • Hybrid Charmonium (ccg): Enhanced rate for D1D; suppress D(*)D(*), Ds(*)Ds(*); K+K-+-; 0 J/, +- should exist Zhu, PLB 625 (2005) 142001 Close & Page, PLB 628 (2005) 215 Kou & Pene, PLB 631 (2005) 164 • Tetraquark (cs)(cs): member of nonet along with X(3872) & X(3940). Must decay into DsDs. Maiani, Riquer, Piccinini, & Polosa, PRD 72 (2005) 031502 • Zhu points out could be a scalar tetraquark (uu+dd)cc but if so then should also observe isovector partner Y’(4260)+-0 J/ • cJ 0 molecule : no decay into 00J/ Liu, Zeng, & Li, PRD 72 (2005) 054023 I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06

  29. Theory (cont’d) • cJ  molecule : 00/+- 0.5; Y(4260)cJ J/, Y(4260)+-0 J/ Yuan, Wang, & Mo, PLB 634 (2006) 399 • Baryonium (tiny KK J/; visible ppy(2S) & D*D*; suppressed DD) Qiao, hep-ph/0510228v1, v2 • Conventional 4S cc (s-d interference suppresses open charm) Llanes-Estrada, PRD 72 (2005) 031503 • Oddball (3g glueball) [ big  rate] • 3S = y(4040) should have a large +-J/ partial width • Coupled channel signal: non-exotic Ds*Ds, D*D*, Ds*Ds*P-wave channels together create Y(4260) Beveren & Rupp, hep-ph/0605317v1 I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06

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