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

2. I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06 2 Y(4260) Discovery BABAR PRL 95, 142001 (2005)  e + e - →  ISR Y(4260), Y(4260)   +  - J/   J PC =1 - -   At a minimum in  (e + e - →hadrons)  Why hasn’t this been seen before?  ( e + e -  J/  )   50 pb -1 at 4.26 GeV (based on ISR rate at BaBar)  R~0.05<<Error on  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

3. I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06 3 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 CLEO & Y(4260)

4. 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) Missing Mass 2 (GeV 2 )

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

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

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

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

9. I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06 9 Direct Production @  s=4260 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 …may prove crtical to reveal the nature of the 4260 Very wide range of decay mode (16) examined @CLEOc

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

11. I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06 11 Build on previous analysis Recall  (3770)  XJ/  : Plot k=missing momentum (radiative photon energy) Small signal at k=0 [direct  (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 RR’s to  (2S) peak  (2S) Tail k, Missing Momentum (MeV) Direct decay RR’s to  (2S) peak  (2S) Tail k, Missing Momentum (MeV) Direct decay Adam et al., PRL 96 (2006) 082004

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

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

14. I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06 14 Results@  s=4260 MeV Channel  (%)N sig N bgd  (pb)B/B(  +  - J/  )  +  - J/  38372.458 +12 -10  41  0  0 J/  2280.323 +12 -8  10.39 +0.20 -0.15  0.02 K + K - J/  2130.079 +9 -5  10.15 +0.10 -0.08  0.02  J/  1652.7<32<0.6  0 J/  221<12<0.2  ’ J/  1101.5<19<0.3  +  -  0 J/  220<7<0.1  J/  61<44<0.8  +  -  (2S)190<20<0.3   (2S)150<25<0.4  c0 91111.5<234<4.0  c1 2613.3<30<0.5  c2 2743.3<90<1.6  +  -  0  c1 90<46<0.8  +  -  0  c2 90<96<1.7 +- +-  1875.5<5<0.1  +  -  : <0.102 BaBar (prelim: hep-ex/0605086)

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

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

17. I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06 17 Open Charm@4260 Hybrid charmonium  Y  D 1 D, D 1 ’ D  (D *  ) D 2-body open charm decomposition crucial to finding a D 1 D 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(D 0 ), angles, lower  s?  s (GeV) D 0 Momentum (GeV/c) D0D0D0D0 D*D D*D*D*D* D*DD*D D*D*D*D* D 1 D ? Total Hadronic Cross Section Sum of 2-Body Exclusive D (*) D (*)

18. 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 f 0 (980) or f 0 (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

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

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

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

22. I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06 22 Datasets E CM (MeV) L (pb -1 )E CM (MeV) L (pb -1 ) 377328141202.8 39703.941404.9 39903.4416010.2 40105.6417055 40151.541805.7 40303.042002.8 40603.3426013.2

23. 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 E cm  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/  )”.)  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

24. I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06 24 KK J/  Kinematically allowed for E cm >4085 Babar sees no signal K/  Separation (#  ) 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

25. 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:  (2S) ~5% Fake J/  subtraction (sidebands): smaller than  (2S  Statistical errors: 16% (     J/  at 4260) or larger

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

27. I. Shipsey Hadron Spectrscopy and Exotics ICHEP06 7/28/06 27 What’s known 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 B  KY(4260) 88 3.1  Aubert et al., PRL 95 (2005) 142001. 4.26 E cm R

28. 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 D 1 D; suppress D (*) D (*), D s (*) D s (*) ; 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 D s D s. 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  0 J/  Liu, Zeng, & Li, PRD 72 (2005) 054023

29. 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   (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 =  (4040) should have a large  +  - J/  partial width  Coupled channel signal: non-exotic D s * D s, D * D *, D s * D s * P-wave channels together create Y(4260) Beveren & Rupp, hep-ph/0605317v1