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XYZ News from Belle. XYZ mesons. Stephen L. Olsen, Univ of Hawaii QWG 2006 June 26-30, Brookhaven. B-factories are Charmonium factories. c c production mechanisms @ a B factory: B meson decays e + e - annihilation gg collisions e + e - radiative return (isr). - PowerPoint PPT Presentation


  • XYZ mesons Stephen L. Olsen, Univ of HawaiiQWG 2006 June 26-30, Brookhaven XYZ News from Belle

  • B-factories are Charmonium factoriescc production mechanisms @ a B factory:

    B meson decays

    e+e- annihilation

    gg collisions

    e+e- radiative return (isr)

  • cc production in B decaysj=j=J = 0 or 1Spectator model says Jcc= 0 or 1 shoulddominate exclusive BK(cc) decays.

  • Allowed decays all have Bf~10-3 from PDG2004hcK 0.9 x10-3J/yK 1.0 x10-3J/yK* 1.4 x10-3yK 0.7 x10-3yK* 0.9 x10-3cc0K 0.6 x10-3cc1K 0.7 x10-3J/yK12701.8 x10-3 BK cc(J=2) still not seen

  • e+e- J/y + (cc)J/yXX (almost) alwayscontains (cc)

    C(X) = +1consistent with bkg hc cc0hc M(X)

  • gg DDJPC = 0++, 2++JPC = 1--cce+e- g (cc)

  • XYZ particles in BelleX(3872) p+p- J/y in BKp+p-J/y

    Z(3930)DD in gg DD

    Y(3940) wJ/y in BK 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/yNEW

  • gg Z(3931) DD at Belle41 11 evts (5.5) M=3931 4 2 MeV=208 3 MeVsin4q (J=2)Matches well to cc2 expectationsM(DD) GeVBelle PRL 96, 082003 (2006)

  • Z(3930): candidate for the cc23931M= 3931 MeV is ~45 MeV low

    G=20MeV too narrow?Masses fromBarnes, Godfrey & SwansonPRD 72, 054026 (2005)

  • e+e- J/y X(3940)e+e-J/y + Xhep-ex 0507019 submitted to PRL

  • X(3940)D*D seen(DD & wJ/y not seen)B(D*D)>45%B(DD)
  • Is the X(3940) the hc?3940M= 3943 MeV is ~150 MeV low


  • X(3872) in BKp+p-J/yM(ppJ/y)yp+p-J/yX(3872)p+p-J/yPRL 91, 262001

  • Also seen in ppX(3872)CDFhep-ex/040602211.6sProduction properties similar to those of the yX(3872)D0 PRL 93, 072004 (2004) PRL 93, 162002 (2004)

  • C=+1 is establishedX(3872)gJ/y seen in:&BellePRL 96 102002M(pp) looks like a rX(3872)wJ/y seenCDF Belle Bellehep-ex/0505037

  • 0++ 0-+qlp |cosqlp| c2/dof = 34/9y|cosq| |cosy| c2/dof=34/9rule out 0++ & 0 -+ereJ/yk(erxeJ/y)Ruled out by Belle

  • Angular analysis from CDFIlya Kravchenko: FPCP061++or2-+

  • Belle: Threshold peak in BKD0D0p0M=3875.4 0.7 0.8 MeVBr(BKX)Bf(XD0D0p0 ) = (1.27 0.31 )x10-4Br(XD0D0p0)Br(Xp+p-J/y)~ 10+0.7-1.7+0.22-0.39M(DDp)DEBelle hep-ex/0606055 today!

  • Comments on the D0D0p0 mass peakFitted M: 3875.4 0.7 0.8 MeV+0.7-1.7M(mD0+ mD*0) = +4.3 0.7 MeV+0.7-1.7PDG052xPDG error on mD0(could be 2.0 MeV)PDG MX3872: 3871.2 0.5 MeVHere error onmD0 drops outNominally ~2.3s above D0D*0 threshold(but errors are non-Gaussian)~2s discrepancyDD* Binding Energy?:

  • X(3872) has no satisfactory cc assignment 3872 Br(gJ/y) too small& Br(rJ/y) too bigcc1 hc2rJ/y ispin forbidden D0D0p0 @ thresh. suppressed BKcc(J=2) suppressedhc2

  • Y(3940) in BK wJ/yM3940 11 MeVG 92 24 MeVPRL94, 182002 (2005)M(wJ/y) MeVG(Y3940 wJ/y) > 7 MeV (an SUF(3) violating decay)~this is 103 x G(y hJ/y) (another SUF(3) violating decay)if the Z(3930) is the cc2the Y(3940) mass is toohigh for it to be the cc1

  • Is there a cc slot for Y(3940) ?Can M(cc1)>M(cc2)?cc1Mass is lowhc cc039403931

  • e+e- gisr Y(4260) at BaBars(e+e-+p-J/)~50 pb G(Y4260p+p- J/y) > 1.6MeV @ 90% CLY(4260)X.H. Mo et al, hep-ex/060302442604260BaBar PRL95, 142001 (2005)Not seen in e+e- hadronsBES data

  • Y(4260) at CLEO-IIIConsistent resultsISR(1S)-(4S)13.3 fb-1R.Poling @ Charm 2006

  • Y(4260) at BelleMXSelect e+e- p+p- +- +X; Nchg=4 M+-=MJ/y30MeV; pJ/y>2 GeV; Mpp>0.4GeV | data4.2
  • BaBar vs CLEO vs Belle-6-4-4.2-16-25-6~2.5s differentFull report from Belle at ICHEP in Moscow-5

  • No 1-- cc slot for the Y(4260) 42804280 X.H. Mo et al, hep-ex/0603024

  • DD** threshold in relation to the Y(4260)4.28-mDD** spectrum M(p+p-J/y) GeVNo obviousdistortions

  • summaryZ(3931) (ggDD)Probably the cc2

    X(3940) (e+e- J/y X)C=+1Could be the hc (albeit with some stretching)

    X(3872):JPC = 1++ Br(Xp+p- J/y) largeBr(XD0D0p0) seen; ~ 10xBr(Xp+p-J/y)


  • summary contd

    Y(3940) G( Y3940 wJ/y) >7 MeV too large for charmonium Mass too low for a hybrid

    Y(4260)Confirmed by Belle but at a higher mass G(y4260p+p-J/y)>1.6 MeV also very large JPC=1--, but not seen in e+e- hadrons- Straddles the D**D threshold, but with no obvious distortions to the ppJ/y line-shape

  • conclusionsThere is a new hadron spectroscopy in the 3.5~4.5 GeV mass regionMaybe more than one The new states are characterized by large partial widths (Bfs) to hadrons+J/y Br(X(3872)rJ/y) > 4.3% (Isospin=1) G(Y(3940)wJ/y) > 7 MeV (SU(3) octet) G(Y(4260)p+p-J/y) > 1.6 MeV There is no apparent transition at the D**D mass threshold

    (mine, not Belles)

  • Thank You

  • Back-up slides

  • Look at e+e-J/y D(D(*))Reconstruct a J/y & a Duse D0K-p+ & D+K-p+p+ Determine recoil mass

  • Inclusive BKx from BaBar?Fully reconstructed B- tags