1. Stephen L. Olsen University of Hawaii PANIC-08 Nov 10-14, 2008 Eilat The XYZ mesons

2. X & Y mesons BaBar B  K  +  - J/  M(  +  - J/  M(J  ) X(3872) B  K  J/  M(  J/  Y(3940) X(3940) X(4160) e + e -  DD*J/  e + e -  D*D*J/  M(DD*)M(D*D*) Y(4260) Belle Y(4008)? e + e -   ISR  +  - J/  Y(4350) & Y(4460) e + e -   ISR  +  -  ’ M(  +  -J/  ) M(  +  -  ’) e + e -   ISR  c  c M(  c  c ) M(  J/  (Decay to final states with a cc pair &  q i =0 ) BaBar Belle

3. Neutral cc X & Y mesons NameJ PC  (MeV) Decay modesExptscomment X(3872)1 ++ <2.3  J/   J/  DD* Belle/CDF/D0/BaBar DD* molecule? X(3940)0 ?+ ~37DD* (not DD,  J/  ) Belle  c ’’(?) Y(3940)? ?+ ~30  J/  (not DD *) Belle/BaBar X(4160)0 ?+ ~140D*D* (not DD, DD*) Belle  c ’’(?) Y(4008)1 -- ~225  J/  Belle Y(4260)1 -- ~80  J  (not  ’) BaBar/CLEO/Belle ccg hybrid? Y(4350)1 -- ~75  ’ (not  J/  ) BaBar/Belle Y(4660)1 -- ~50  ’;  c  c (?) Belle @  c  c threshold

4. predicted measured Are any of these standard cc charmonium?

5. 3872MeV ?? Is the 1 ++ X(3872) the  c1 ’ (2 3 P 1 ) ? Mass is too low  c1 ’   J/  violates Ispin Bf(X 3872   J/  )>4%  (  J/  ) should be >>  (  J/  ) expt:  (  J/  ) <<  (  J/  )

6. Neutral cc X & Y mesons NameJ PC  (MeV) Decay modesExptscomment X(3872)1 ++ <2.3  J/   J/  DD* Belle/CDF/D0/BaBar DD* molecule? X(3940)0 ?+ ~37DD* (not DD,  J/  ) Belle  c ’’(?) Y(3940)? ?+ ~30  J/  (not DD *) Belle/BaBar X(4160)0 ?+ ~140D*D* (not DD) Belle  c ’’(?) Y(4008)1 -- ~225  J/  Belle Y(4260)1 -- ~80  J  BaBar/CLEO/Belle ccg hybrid? Y(4350)1 -- ~75  ’ BaBar/Belle Y(4660)1 -- ~50  ’;  c  c (?) Belle @  c  c threshold It is pretty widely --but not universally-- accepted that the X(3872) is not a standard cc charmonium state. For a dissenting view, see C Meng & KT Chao PRD 75,114002 (2007)

7. Could the Y(3940) be charmonium? Bf(B  KY 3940 )xBf(Y 3940   J/  )  (MeV) Belle(7.1 ± 3.1) x 10 -5 87±34 BaBar(4.9 ± 1.1) x 10 -5 33±12 Avg(5.2 ± 1.0) x 10 -5 39±11 assuming Bf(B  KY 3940 )<Bf(B  KJ/  ) = 1.0x10 -3  (Y 3940   J/  )>1MeV True for all other B  K(cc) transitions >10x higher than any measured cc hadronic transition

8. Neutral cc X & Y mesons NameJ PC  (MeV) Decay modesExptscomment X(3872)1 ++ <2.3  J/   J/  DD* Belle/CDF/D0/BaBar DD* molecule? X(3940)0 ?+ ~37DD* (not DD,  J/  ) Belle  c ’’(?) Y(3940)? ?+ ~30  J/  (not DD *) Belle/BaBar X(4160)0 ?+ ~140D*D* (not DD) Belle  c ’’(?) Y(4008)1 -- ~225  J/  Belle Y(4260)1 -- ~80  J  BaBar/CLEO/Belle ccg hybrid? Y(4350)1 -- ~75  ’ BaBar/Belle Y(4660)1 -- ~50  ’;  c  c (?) Belle @  c  c threshold

9. X(3940) & X(4160) =  c ” &/or  c ’’’ ? 3940MeV 4160MeV One, or the other, could be the  c ”, but it seems very unlikely that one is the  c ” and the other is the  c ’’’ c”c”  c ’’’

10. Neutral cc X & Y mesons NameJ PC  (MeV) Decay modesExptscomment X(3872)1 ++ <2.3  J/   J/  DD* Belle/CDF/D0/BaBar DD* molecule? X(3940)0 ?+ ~37DD* (not DD,  J/  ) Belle  c ’’(?) Y(3940)? ?+ ~30  J/  (not DD *) Belle/BaBar X(4160)0 ?+ ~140D*D* (not DD) Belle  c ’’(?) Y(4008)1 -- ~225  J/  Belle Y(4260)1 -- ~80  J  BaBar/CLEO/Belle ccg hybrid? Y(4350)1 -- ~75  ’ BaBar/Belle Y(4660)1 -- ~50  ’;  c  c (?) Belle @  c  c threshold ?????

11. 1 -- ISR Y states not seen in D ( * ) D ( * ) D*D*D*D* DD*DD*  (4040)  (4160) Y(4008)  (4415) Y(466 0) Y(4260) Y(4350) DD DDπ Λc+Λc–Λc+Λc– ? σ(e + e – → open charm) NEW  (3770) if R uds =2.285±0.03 Durham Data Base Y(4008)  (4040)  (4160) Y(4260) Y(4350)  (4415) Y(4660) Belle: Sum of all measured exclusive contributions This means that the ISR Y states have  (  J/  (  ’)) > 1 MeV PRD 77, 01103 PRL 98,092001 PRL 100,062001 PRL 101,172001 G.Pakhlova et al (Belle): Too large for charmonium

12. only 1 unassigned 1 -- cc slot

13. Neutral cc X & Y mesons NameJ PC  (MeV) Decay modesExptscomment X(3872)1 ++ <2.3  J/   J/  DD* Belle/CDF/D0/BaBar DD* molecule? X(3940)0 ?+ ~37DD* (not DD,  J/  ) Belle  c ’’(?) Y(3940)? ?+ ~30  J/  (not DD *) Belle/BaBar X(4160)0 ?+ ~140D*D* (not DD) Belle  c ’’(?) Y(4008)1 -- ~225  J/  Belle Y(4260)1 -- ~80  J  BaBar/CLEO/Belle ccg hybrid? Y(4350)1 -- ~75  ’ BaBar/Belle Y(4660)1 -- ~50  ’;  c  c (?) Belle @  c  c threshold ????? At most 1 of the 1 -- Y states can be conventional cc charmonium

14. The Z mesons Electrically charged counterparts of the X & Y mesons

15. The Z meson candidates M(  ±  ’ ) GeV BK +’BK +’ Z(4430) M 2 (  ±  ’ ) GeV 2 M 2 (  ’ ) GeV 2 M(  ±  c1 ) GeV B  K  +  c1 M 2 (  ’ ) GeV 2 M 2 (  ±  ’ c1 ) GeV 2 Z 1 (4050) Z 2 (4250) 6.5  >6  R.Mizuk,R.Chistov et al (Belle) PRD 78, 072004 S.-K. Choi et al (Belle) PRl 100, 142001

16. Z meson properties NameMass(MeV)Width(MeV)Decay mode Z(4430)4433±545 +35 -18 +’+’ Z 1 (4050)4051 +24 -43 82 +51 -29  +  c1 Z 2 (4250)4248 +185 -45 177 +320 -72  +  c1 Can’t be cc charmonium minimal quark content: ccud dc u c

17. Still controversial Arafat Gabareen Mokhtar talk at ICHEP-2008 Z(4430) not confirmed by BaBar (but neither do they rule it out). B.Aubert et al (BaBar) arXiv/0811.0564 BaBar Belle A full Dalitz-plot analysis of the Belle B  K  +  ’ data will be reported at next month’s QWG meeting in Nara

18. What could they XYZ states be?

19. suggested possibilities (some references in backup slides) D ( * ) D ( * ) molecules (real or virtual) masses should be near M(D ( * ) )+M(D ( * ) ) mass thresholds Favored model for X 3872 M(D 0 )+M(D* 0 )=3871.8±0.4 M(X 3872 )=3871.4±0.4 diquark-diantiquarks Expect SU(3) multiplets cc-gluon hybrids LQCD: M>~4.3 GeV Open charm thresh =M D +M D**  4285 (above Y 4260 peak) Non-zero charges are not allowed

20. Thresholds some of the states are near thresholds, but this is not a universal feature DSDSDSDS D(*)D(*)D(*)D(*) (*) (*)(*) (*) ?? No  exchng for D S D S

21. no evidence for multiplet partners u c c u d c c d d c c u u c c d X u (3872)X d (3872) X + (3872) X - (3872) Expect: Bf(B 0  K - X + )Bf(X +      J/  ) Bf(B -  K - X 0 )Bf(X +      J/  ) B +  K - X u B 0  K 0 X d M(X d )-M(X u )= 2(m d -m u )/cos  L Maiani et al PRD 71,014028 (20050  8 ± 3 MeV ≈ 2 diquark-diantiquark expectations:

22. no X ± (3872) isospin partner is seen B 0  K ± p ∓ p 0 J/y B ∓  K S p ∓ p 0 J/y Bf(B 0  K - X + )Bf(X +  p + p 0 J/y) Bf(B -  K - X 0 )Bf(X +  p + p - J/y) < 0.4 (expect  2) ?? B. Aubert et al (BaBar) PRD 71, 031501 BaBar

23. B 0  K S X d & B  K ± X u with X u =X d ?  M = 0.22 ± 0.90 ± 0.27 MeV Compared to 8±3 MeV (Maiani et al PRD 71 014028) BaBar, arXiv: 0803.2838 K S mode K ± mode K S mode K ± mode  M = 2.7 ± 1.6 ± 0.4 MeV Belle BaBar

24. What about in the X3872  DD* channel? PRL 97,162002,2006 B  K D 0 D 0  0 6.4σ PRD77,011102,2008 B + & B 0  D 0 D *0 K 4.9σ NEW 347fb -1 M=3875.2±0.7 +0.9 -1.8 ~2  higher than M in  J/  mode M=3875.1 +0.7 ±0.5 -0.5 ~4  higher than M in  J/  mode Is this Maiani et al’s partner particle?

25. New results on X 3872  DD* from Belle B  K D 0 D *0 605 fb -1 D*→DγD*→Dγ D*→D0π0D*→D0π0 Preliminary Flatte vs BW similar result: 8.8σ M=3872.6 +0.5 ±0.4 MeV -0.4 Agrees with M from  J/  mode N.Zwahlen, T.Aushev et al (Belle) arXiv/0810.0358 More details in Tagir Aushev’s talk @ this meeting

26. How about cc-gluon hybrids? cc qq-gluon excitations predicted 30 yrs ago LQCD: lowest 1 -- cc-gluon mass ~4.3 GeV - QCD sum rules get lower values ~3.7 GeV relevant open charm threshold is D**D (~4.28 GeV)  (  J/  ) larger than that for normal charmonium  (e + e - ) for 1 -- states less than 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) Kisslinger et al, arXiv 0805.1943 (2008) Y(4260) seems to match all of these !!!

27. 3.85- 3.88- 4.28- 4.36- DD D D D D D 4.66- 4285 DD** thresholds and the Y(4260), Y(4360) & Y(4660) 4.26- Y(4360) & Y(4660) well above all DD** thresholds Belle

28. Scoreboard candidateMolecule?cq cc-gluon X(3872) X(3940) Y(3940) X(4160) Y(4008) Y(4260) Y(4350) Y(4660) Z(4430) Z 1 (4050) Z 2 (4250) ??

29. No model can accommodate all

30. Are there XYZ counterparts in the b- and s-quark sectors?

31. Y(4260) equivalent with b-quarks?  (e + e -       (nS)) Peaks not consistent with known bb states  (  (nS) ~ 1000x too large for bottomonium K.F. Chen et al (Belle) arXiv:0808.2445 Belle

32. Y(4260) equivalent with s-quarks?  (e + e -       (1020)) Y(2175)  f 0 (980)  e+e-   f 0 (980)  M(f 0 (980)  f 0 (980)   +  - BaBar

33. Confirmed by BES & Belle confirmed by BESII in J/    f 0 (980) M(f 0 (980)  GeV M.Ablikim et al (BES) PRL 100, 102003 (2008) X.L. Wang et al (Belle) arXiv: 0808.0006  (e + e -  f   (1020)) BelleBES

34. Maybe the X(1835) is one too? M. Ablikim et al (BESII), Phys.Rev.Lett.95:262001,2005 J/    X(1835) |       ’ X(1835) mostly ss BES

35. Concluding remarks A number of “mysterious” mesons have been observed They have large hadron-charmonium partial widths –Much larger than those seen in the charmonium system There is no strong variations above DD** thresholds –As expected for cc-gluon hybrids Some are near thresholds but not all –As expected for molecules, threshold cusps, etc. No Isospin or SU(3) multiplet partners yet seen –As expected for diquark-diantiquark models Similar structures in b- & (maybe) s-quark sectors

36. However, none of the proposed models have produced a compelling match to the experimental observations

37. 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?

38. Thank you

39. Backup Slides

40. Some recent reviews Galina Pakhlova arXix:0810.4114 –This includes 64 references –See slides from her plenary talk @ ICHEP08 S.-K. Choi arXiv:0810:3546 –See slides from her parallel talk @ ICHEP08 E. Braaten arXiv:0808.2948 –48 references, mostly on molecular-like models S. Godfrey & S.L.O. arXix:0801.3867 –128 references, but almost a year old

41. Some theory references c c  c1 ’ charmonium? C Meng & KT Chao PRD 75,114002 (2007) NA Tornqvist PLB 590, 209 (2004) ES Swanson PLB 598,197 (2004) E Braaten & T Kusunoki PRD 69 074005 (2004) CY Wong PRC 69, 055202 (2004) MB Voloshin PLB 579, 316 (2004) F Close & P Page PLB 578,119 (2004) … L Maiani et al PRD 71,014028 (2005) T-W Chiu & TH Hsieh PRD 73, 111503 (2006) D Ebert et al PLB 634, 214 (2006) H Lipkin & M Karliner PLB 638, 221 (2006) … too light?? P Lacock et al (UKQCD ) PLB 401, 308 (1997)

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