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Evidence for Exotic Mesons

Evidence for Exotic Mesons

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Evidence for Exotic Mesons

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  1. Evidence for Exotic Mesons Stephen Olsen U. of Hawai’i & 高能所 北京 BaBar Belle Workshop on light flavors & chiral dynamics 北大Sept 29-30,2007

  2. Talk outline Y(4008) Y(4260) Z(4430) X(3872) X(3940) Y(4780) Y(4660) X(4160) Y(3940) Y(4325)

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

  4. Fabulously successful mesons q q

  5. QCD suggests non-qq meson spectroscopies Glueballs: gluon-gluon color singlet states Multi-quark mesons: molecules: diquark-antidiquark: qq-gluon hybrid mesons c d c d c d d c c c

  6. Searching for non-QPM hadrons is a risky business

  7. forget Remember the pentaquark Q+(1530)? T.Nakano et al (LEPS) PRL 91 012002 (2003)  742 citations

  8. You never can be sure: Is mother nature is smiling at you? or something else.

  9. The XYZ mesons: candidates for non-qq states u c 4 quark candidates (from Belle) u c c c “hybrid” qq-gluon candidates (from Babar & Belle)

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

  11. 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

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

  13. Lots new on the “XYZ” particles Status spring 2007: New Belle/BaBar results: (Summer 2007) • X(3872) • p+p- J/y in BKp+p-J/y • Z(3930) • DD in gg DD • Y(3940) • wJ/y in BK wJ/y • X(3940) • e+e-J/y X & e+e-  J/y DD* • Y(4260) • p+p-J/y in e+e-g p+p- J/y • Y(4325) • p+p-y’ in e+e-g p+p-y’ X(3880)DD - e+e-  J/y DD confirmed by BaBar updated by Belle Y(4008)? X(4160)D*D* - e+e-  J/y D*D* Y(4250) Y(4370) Z+(4430)p+y - BKp+y’ Y(4660)

  14. I’ll concentrate on recent results.

  15. X(3872) >300 citations

  16. X(3872) properties (PDG2007) MeV MD0 + MD*0 = 3.871.8 ± 0.4

  17. M(pp) looks like rpp CDF Belle PRL 96 102002 c2/dof = 43/39 (CL=28%) kinematic limit≈mr • Belle & CDF: JPC = 1++ most likely

  18. What’s new with the X(3872)? BaBar confirms Belle’s DDp threshold enhancement Both groups see a high mass value Mass is 3.8±1.2 MeV above WAvg X(3872)ppJ/y mass; (~3s) is this significant?

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

  20. Is there a cc slot for the X(3872)? 1++(cc1’) 3872 • Br(gJ/y) too small • Br(rJ/y) too big 2-+(hc2) • hc2rJ/y ispin forbidden • D0D0p0 @ thresh.suppressed • BKcc(J=2) suppressed

  21. Y(3940) in BK wJ/y Belle PRL94, 182002 (2005) M≈3940 ± 11 MeV G≈ 92 ± 24 MeV M2(wJ/y) GeV2 M2(Kw) GeV2 M(wJ/y) MeV

  22. Y(3940) properties G(Y3940 wJ/y)> 7 MeV (an SUF(3) violating decay) ~ this is 103 x G(y’  hJ/y) (another SUF(3) violating decay) M(wJ/y) MeV if the Z(3930) is the cc2’ the Y(3940) mass is too high for it to be the cc1’ Belle PRL94, 182002 (2005)

  23. Confirmed by BaBar this summer G.Cibinetto EPS-2007 B±K±wJ/y B±K±wJ/y B0KSwJ/y M2(Kw) ratio M(wJ/y) Some discrepancy in M & G; general features agree

  24. Is there a cc slot for Y(3940) ? hc” Mass is low cc1’ Can M(cc1’)>M(cc2’)? 3940 3931 cc0’ “ “ “ “ For any charmonium assignment, G[Y(3940)w J/y] is too large.

  25. Belle updates e+e-J/yD(*)D(*) Use “partial reconstruction technique” Continuum e+e- annihilation J/y e+ e- reconstruct these D(*) D(*) “Recoil” D(*) undetected (inferred from kinematics)

  26. J/yD(*) recoil mass Partial reconstruction Belle arXiv:0708.3812 J/yDD* J/yDD reconstruct J/yD*D* J/yDD*

  27. M(DD*): Confirm X(3940)DD* D-reconstructed D*-tag 6.0  M = 3942 +7± 6 MeV Gtot = 37 +26 ±12 MeV Nsig =52 +24 ± 11evts -6 -15 D sidebands -16 arXiv:0708.3812 Previous values: M = (3943 ± 6 ± 6) MeV G = (15.4  10.1) MeV G < 52 MeV at 90%CL Bg subtracted PRL 98, 802001 (2007)

  28. Is there a cc slot for X(3940) ? Mass is ~ 60 MeV low (if y(3S) = y(4040)) hc” cc1’ Mass is > M(cc2’) & no cc1 recoil seen 3940 3931 cc0’ Mass is > M(cc2’) & DD decays not seen Maybe the hc”

  29. M(DD): Broad threshold enhancement D-reconstructed D-tag Relativistic BW D sidebands Bg subtracted Resonance? Thresh effect? … ? 3.8  arXiv:0708.3812

  30. M(D*D*)a new state at ~4160 MeV D*-reconstructed + D*-tag 5.5  M = 4156 +25± 15 MeV Gtot = 139 +111 ± 21MeV Nsig =24 +12 ± 11evts -20 -61 -8 arXiv:0708.3812 if 0++, why is it not seen in DD It has to have C=+; most likely 0-+,... possibly 0++

  31. A cc assignment for X(4160) ? Mass is too high (if y(3S)=y(4040)) or too low (if y(3S) = y(4160)) hc” 3940 Mass is far too low (unless y(4S)=y(4160), but, then, where is y(2D?)) 3931 hc’’’ Can place either the X(3940) or X(4160), but probably not both.

  32. The 1-- states seen in ISR

  33. 233 fb-1 e+e- gisr Y(4260) at BaBar BaBar PRL95, 142001 (2005) fitted values: M=4259  8 +2 MeV G = 88  23 +6 MeV -6 -9 Y(4260) ~50pb

  34. Not seen in e+e- hadrons ~3nb 4260 speak(Y(4260)+p-J/)~50 pb Huge by charmonium standards BES data 4260 G(Y4260p+p- J/y) > 1.6MeV @ 90% CL X.H. Mo et al, PL B640, 182 (2006)

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

  36. M(pp) near 4008 & 4260 MeV 3.8 < M(ppJ/y) <4.2 GeV 4.2 < M(ppJ/y) <4.4 GeV

  37. No 1-- cc slot for the Y(4260) X.H. Mo et al, hep-ex/0603024 4260 4280

  38. Is the Y(4260) a cc-gluon hybrid? c c • 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) • G(ppJ/y) larger than that for normal charmonium • G(e+e-) smaller than that for ordinary charmonium Horn & MandulaPRD 17, 898 (1977) Y(4260) seems to match all of these!!! 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)

  39. DD** thresholds in & “Y(4260)” D2D D** spectrum D1D No obvious distortions 4.28-mD M(p+p-J/y) GeV

  40. BaBar p+p-y’ peak at 4325MeV D2D 298 fb-1 (BaBar) hep-ex/0610057 e+e-gISRp+p-y’ D1D Nevt = 68 (<5.7 GeV/c2) Nbkg = 3.1 1.0 M=4324  24 MeV G = 172  33 MeV above all D**D thresholds Not Compatible with the Y(4260) BaBar PRL 98 252001 (2007) S.W.Ye QWG-2006 June 2006

  41. 4325 MeV p+p-y’ peak in Belle (new) Two peaks! (both relatively narrow) (& both above D**D thresh) (& neither consistent with 4260) M=4361  9 ±9 MeV G = 74  15 ±10 MeV M=4664  11 ±5 MeV G = 48  15 ±3 MeV 4260 BaBar values M=4324  24 MeV G = 172  33 MeV X.L. Wang et al (Belle) arXiv:0707.3699 548 fb-1

  42. Y(4660)  f0(980)y’? 4.0 < M(ppy’) <4.5 GeV 4.5 < M(ppy’) <4.9 GeV f0(980)?

  43. K+K- J/y from Belle(very new) M=4875  132 MeV G = 630  126 MeV y(4415)? M=4430 +38 MeV G = 254 +55 MeV -43 -46 4260 C.Z.Yuan et al (Belle) arXiv:0709.2565

  44. M(K+K-)

  45. Latest News electrically charged!!

  46. M(p±y’) from BK p± y’ M = 4433 ±4 ±1 MeV Gtot = 45 +17+30 MeV Nsig =124 ± 31evts K*Kp Veto Veto K2*Kp? -13 -11 M2(py’) GeV2 6.5 M(py’) GeV M2(Kp) GeV2 K. Abe et al (Belle) arXiv:0708.1790

  47. Could this be a reflectionfrom the Kp channel?

  48. Cos qp vs M2(py’) p qp y’ K +1.0 22 GeV2 (4.43)2GeV2 0.25 M2(py’) cosqp 16 GeV2 -1.0 M (py’)& cosqp are tightly correlated; a peak in cosqp peak in M(py’)

  49. Can interference between Kp partial waves produce a peak? Only S-, P- and D-waves seen in data interfere Add incoherently

  50. Can we make a peak at cosqp≈0.25with only S-, P- & D-waves? Not without introducing other, even more dramatic features at other cosqp (&,, other Mpy’) values.