1. Stephen Olsen U. of Hawai’i & 高能所 北京 YZ e otic X Mesons Sookyung Choi Scientist of the month Aug 2004, Korea

2. Constituent Quark Model (CQM) (& 6 antiquarks) Mesons: qq c:c: c +2/3 c:c: C -2/3  + : s -1/3 s +1/3 c -2/3 u -2/3 b +1//3 u +2/3  - : b -1/3 S =1/3 b +1/3 t -2/3 c +2/3 b -1/3 t +2/3 6 quarks Baryons: qqq u -2/3 d +1/3 s +1/3 u +2/3 d -1/3 s -1/3 Gell-Mann Zweig

3. Fabulously successful mesons q q

4. Are there other color-singlet arrangements? Pentaquarks: e.g. an S=+1 baryon (only anti-s quark has S=+1) Glueballs: gluon-gluon color singlet states Multi-quark mesons: qq-gluon hybrid mesons uc u c cc u d u s d Non-quark model states expected in QCD

5. Our approach:look for non-qq mesons cc uc u c 4 (& 6) quark states “hybrid” qq-gluon states u u u u d d

6. Beijing Spectrometer (BES)

7. J/    pp C -2//3 c +2/3 u +2/3 u -2/3 d -1/3 u +2/3 d +1/3 u -2/3 p p 

8. J/    pp This is the  c  pp What is this??? M(pp) GeV J.Z. Bai et. al (BES). PRL 91, 022001 (2003)

9. Fit the M(pp) distribution Best fit to this peak is a resonance with peak mass below the pp mass threshold M=1835 MeV no know  100MeV resonance

10. A pp bound state (baryonium)? p npp deuteron: loosely bound 3-q 3-q color singlets with M d = 2m p -  baryonium: loosely bound 3-q 3-q color singlets with M b = 2m p -  ? attractive nuclear force attractive force? There is lots & lots of literature about this possibility

11. Expectation for pp bound state meson m p +m p Above threshold X  pp ~100% below-threshold p and p annihilate to mesons I=0, J PC =0 -+ init. state: pp       ’ is common

12. Look in J/        ’ M(      ’) M=1833 MeV  70MeV m p +m p 

13. X(1835): “6-quark” meson? 3 quarks + 3 antiquarks Need to confirm J PC of the      ’ peak is 0 -+ Need to find it in other common 0 -+ pp annihilation channels jobs for BESIII u u u u d d

14. Charmonium is of particular interest because it is an especially good system to use to search for non-qq mesons

15. a cc meson has to fit into one of these slots: If it doesn’t, it is a good candidate for a non qq meson

16. B-factories produce lots of cc pairs 0 -+, 1 - - or 1 ++ 0 -+, 0 ++, 2 ++ C =+ states 1 - - only

17. Lots new on the “XYZ” particles X(3872) –     J/  in B  K     J/  Z(3930) –DD in   DD Y(3940) –  J/  in B  K  J/  X(3940) – e + e -  J/  X & e + e -  J/  DD* Y(4260) –     J/  in e + e -      J/  Y(4325) –  +  -  ’ in e + e -   +  -  ’ Y(4008)? Y(4250) Y(4370) Y(4660) X(3880)  DD - e + e -  J/  DD X(4160)  D*D* - e + e -  J/  D*D* Z + (4430)   +  - B  K  +  ’ New Belle/BaBar results: (Summer 2007) Status spring 2007: confirmed by BaBar updated by Belle

18. I’ll concentrate on recent results.

19. X(3872) S-K Choi, SL Olsen et al,

20. X(3872) properties (PDG2007) M D0 + M D*0 = 3.871.8 ± 0.4 MeV

21. M(  ) looks like     2 / dof = 43/39 (CL=28%) kinematic limit≈m  PRL 96 102002 CDF Belle Belle & CDF: J PC = 1 ++  most likely

22. What’s new with the X(3872)? BaBar confirms Belle’s DD  threshold enhancement Mass is 3.8 ± 1.2 MeV above WAvg X(3872)   J/  mass; (~3  is this significant? Both groups see a high mass value

23. Belle’s B  K S X & B  K ± X comparison  M = 0.22 ± 0.90 ± 0.27 MeV K S modeK ± mode “molecular” models predicted this to be <<1 (Braaten et al PRD 71 074005) “diquark-antidiquark” models predicted this to be 8±3 MeV (Maiani et al PRD 71 014028) Confirms an earlier BaBar result

24. Is there a cc slot for the X(3872)? 3872   r  J/  too small   r (  J/  ) too big 1 ++  (  c1 ’)   c    J/  ispin forbidden  D 0 D 0  0 @ thresh.suppressed  B  Kcc(J=2) suppressed 2 -+ (  c2 )

25. Y(3940) in B  K  J/  M≈3940 ± 11 MeV  ≈ 92 ± 24 MeV Belle PRL94, 182002 (2005) M(  J/  ) MeV M 2 (K  ) GeV 2 M 2 (  J  ) GeV 2 S-K Choi, SL Olsen et al,

26. Y(3940) properties Belle PRL94, 182002 (2005) M(  J/  ) MeV  (Y 3940   J/  > 7 MeV (an SU F (3) violating decay) ~ this is 10 3 x  (  ’   J/  (another SU F (3) violating decay) if the Z(3930) is the  c2 ’ the Y(3940) mass is too high for it to be the  c1 ’

27. Confirmed by BaBar this summer B ±  K ±  J/  B 0  K S  J/  M 2 (K  )  J  ) ratio Some discrepancy in M &  ; general features agree G.Cibinetto EPS-2007

28. Is there a cc slot for Y(3940) ? Can M(  c1 ’)>M(  c2 ’)?  c1 ’ Mass is low c”c” “ “  c0 ’ 3940 3931 For any charmonium assignment,  [Y(3940)   J/  is too large.

29. The 1 -- states seen in ISR   ’)

30. e + e -   isr Y(4260) at BaBar 233 fb -1 Y(4260) BaBar PRL95, 142001 (2005) ~50pb M=4259  8 +2 MeV  = 88  23 +6 MeV -6 -9 fitted values:

31. Not seen in e + e -  hadrons  (Y4260      J/  ) > 1.6MeV @ 90% CL X.H. Mo et al, PL B640, 182 (2006) 4260 BES data ~3nb  peak  Y(4260)  +   J/  pb Huge by charmonium standards

32. “Y(4260)” at Belle (New) M=4247  12 +17 MeV  = 108  19 ± 10 MeV -32 M=4008  40 +114 MeV  = 226  44 ± 87 MeV -28 ??? C.Z Yuan et al (Belle) arXiv:0707.2541 To appear in PRL M=4259  8 +2 MeV  = 88  23 +6 MeV -6 -9 BaBar values: Resonance? Thresh effect? …?

33. No 1 -- cc slot for the Y(4260) 4260 X.H. Mo et al, hep-ex/0603024

34. Is the Y(4260) a cc-gluon hybrid? cc qq-gluon excitations predicted 30 yrs ago lowest 1 -- cc-gluon mass expected at ~4.3 GeV relevant open charm threshold is D**D (~4.28 GeV)  (  J/  ) larger than that for normal charmonium  (e + e - ) smaller than that for ordinary charmonium Horn & Mandula PRD 17, 898 (1977) Banner et al, PRD 56, 7039 (1997); Mei & Luo, IJMPA 18, 15713 (2003) Isgur, Koloski & Paton PRL 54, 869 (1985) McNeile, Michael & Pennanen PRD 65, 094505 (2002) Close & Page NP B443, 233 (1995) Y(4260) seems to match all of these !!!

35. DD** thresholds in & “Y(4260)” 4.28-m D D** spectrum M(     J/  ) GeV No obvious distortions D1DD1D D2DD2D

36. BaBar’s      ’ peak at 4325MeV Nbkg = 3.1  1.0 Nevt = 68 (<5.7 GeV/c 2 )  2 -prob < 5.7 GeV/c 2 Y(4260) 6.5  10 -3  (4415)1.2  10 -13 Y(4320)29% e + e -   ISR      ’ M=4324  24 MeV  = 172  33 MeV above all D**D thresholds S.W.Ye QWG-2006 June 2006 Not Compatible with the Y(4260) D1DD1D D2DD2D 298 fb -1 (BaBar) hep-ex/0610057 BaBar PRL 98 252001 (2007)

37. 4325 MeV      ’ peak in Belle (new) M=4324  24 MeV  = 172  33 MeV 548 fb -1 X.L. Wang et al (Belle) arXiv:0707.3699 Two peaks! M=4664  11 ± 5 MeV  = 48  15 ± 3 MeV M=4361  9 ± 9 MeV  = 74  15 ± 10 MeV BaBar values (both relatively narrow) (& both above D**D thresh) (& neither consistent with 4260) 4260

38. Latest News electrically charged!! S-K Choi, SL Olsen et al, Belle, submitted to PRL

39. M(  ±  ’) from B  K  ±  ’ M 2 (K  ) GeV 2 M 2 (  ’ ) GeV 2 K. Abe et al (Belle) arXiv:0708.1790 K*  K  K 2 *  K  Veto M(  ’ ) GeV 6.5  M = 4433 ± 4 ±1 MeV  tot = 45 +17 +30 MeV Nsig =124 ± 31evts -13-11

40. Comments on the Z + (4430) Not a reflection from the K  system ~ No significant signal in B  K  J/  It has non-zero charge  not cc or hybrid Mass, width & decay pattern similar to Y(4360) & Y(4660)

41. conclusions There seems to be a new hadron spectroscopy in the M=3.5~5 GeV region –Maybe more than one –Bodes well for BESIII, Super-B factories & PANDA Some states are narrow even though they are far above decay thresholds –e.g. Y(4660)   ’ & Z + (4430)     ’ have large Q but  ≈50 MeV characterized by large partial widths (Bfs) to hadrons+J/  (or  ’)  – Br(X(3872)   J/  ) > 4.3% (Isospin=1) –  (Y(3940)   J/  ) > 7 MeV (SU(3) octet) –  (Y(4260)      J/  ) > 1.6 MeV States that decay to  ’ not seen decaying to J/  (and vice-versa) –Bf(Y(4660)   ’) >> Bf(y(4660)   J/  )  same for Y(4360) & Z(4430   ’ –Y(4260) not seen in Y(4260)   ’ The new 1 -- states are not apparent in the e + e -  D ( * ) D ( * ) cross sections There is no evident transitions at the D**D mass threshold (mine)

42. New 1 -- states     J/      J/   ’ ’

43. some of the states are near thresholds, but this is not a universal feature D S D S thresholdsDD thresholds

44. D*D* DD* DD  tot Y(4660)Y(4360) Y(4260) Y(4008) None of the 1 -- peaks match structures in e + e -  hadrons Pakhlova (Belle) PRL 98, 092001 (2007)

45. Lots of pieces Y(4360) Y(4660) Y(4260) Y(4008) X(3872) X(3940) X(4160) Z(4430) Y(3940) Are they all from the same puzzle?

46. 謝謝

47. Actual fit M=1830.6 ± 6.7 MeV/c 2  < 153 MeV/c 2 (90% CL) J/    pp in the BES expt 00.10.20.3  2 /dof=56/56 fitted peak location