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New Resonances at Belle Jolanta Brodzicka INP Kraków, for the Belle Collaboration ICFP 2005

New Resonances at Belle Jolanta Brodzicka INP Kraków, for the Belle Collaboration ICFP 2005 October 4 th , 2005 Taiwan. Outline ‘ old’ X(3872) properties (in B K X) Y(3940) in BK  J/ X(3940) in double charm production Z(3930) in γγ production Summary.

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New Resonances at Belle Jolanta Brodzicka INP Kraków, for the Belle Collaboration ICFP 2005

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  1. New Resonances at Belle Jolanta Brodzicka INP Kraków, for the Belle Collaboration ICFP 2005 October 4th, 2005 Taiwan • Outline • ‘old’ X(3872) properties (in BK X) • Y(3940) in BK  J/ • X(3940) in double charm production • Z(3930) inγγproduction • Summary

  2. M and  do not fit well any potential model cc states • Speculations: X is a D*0D0 bound state (predicted by Tornqvist 1994) • JPC= 1++ favored by some models (Swanson, PLB 588, 189(2004)) expected admixture of (782)J/ and (770)J/ components, in addition to D*0D0 (isospin viol. decays) Intriguing X(3872) • X(3872)+- J/ discovered by Belle in 2003 in B+K++- J/ M= 3872.0 ± 0.6 ± 0.5 MeV  ~ MD*0 + MD0 <2.3 MeV @90% C.L.  narrow BF(BK X)BF(X+-J/)=1.31±0.24±0.13 10-5 • Confirmed by other exp. (D0, CDF, BaBar), included in PDG2005 PRL 91, 262001 253fb-1 N=49.18.4 X+- J/ M(+-J/) Jolanta Brodzicka, INP Kraków New Resonances ICFP 2005

  3. X(3872) region N=13.6±4.4 (4.0) M(J/) (XJ/) = 0.14±0.05 (X+-J/) Evidence for X(3872) J/ • If X(3872)  J/  C=+1 for X(3872)  search for BKX, XJ/ • Mbc distributions in M(J/) bins  BKJ/ signal seen only for M(J/)~MX(3872) • Fit Mbc in M(J/) bins  BK J/ signal yield vs M(J/) hep-ex/0505037 BF(BKX)BF(XJ/)=1.8±0.6±0.110-6  CX(3872) =+1 established Theory expects: ~40 for X(3872)=’c1(23P1) Jolanta Brodzicka, INP Kraków New Resonances ICFP 2005

  4. Virtual (782)? N=12.4±4.1 (4.3) Bkd=2.1±1.0 (782) Γ=8.4MeV M(+-0 ) BF(X +-0 J/) =1.0 ±0.4 ±0.3 BF( X +-J/) X(3872) J/ sub-threshold decay hep-ex/0505037 • Search for BK X(3872), X(3872)J/, +-0 • Mbcvs. Efitted in M(+-0) bins BKX,X+-0 J/ signal yield vs. M(+-0) • Significant B signal only for M(+-0)>750 MeV • Support for molecular D*0D0 interpretation (Swanson) • Further evidence of C=+1 for X(3872)  large isospin violation! Jolanta Brodzicka, INP Kraków New Resonances ICFP 2005

  5. S-wave 2/d.o.f=43/39 favored M(+-) P-wave 2/d.o.f=71/39 disfavored N=12.5±3.9 (>5) Constraints on JPC of X(3872) I • Fit to M(+-) • if C=+1: +-J/ is primarily J/ • JPC(X)= J++ :  and J/ in a S/D-wave • J-+ :  and J/ in a P-wave • M(+-) at kinematical limit is suppressed by (p*J/)2L+1  shape of high-mass part of M(+-) provides some JPC information hep-ex/0505038 J++ is favored • X(3872) D0D00 observation • BKD0D00/KD0D*0candidates selected using E-Mbc • Enhancement in M(D0D00)MX observed • Difficult to distinguish D0D00/D0D*0 BF(BK X)BF(XDD)=1.6±0.4±0.310-4 Preliminary • XDD suggests that J2 is unlikely, (at least 1 pair in D-wave, suppressed by p* 5) Jolanta Brodzicka, INP Kraków New Resonances ICFP 2005

  6. 2/d.o.f=18/9 MC expectations 2/d.o.f=34/9 |cos| |cos| Constraining JPC[X(3872)] from angular distr. • Full angular analysis limited by low statistics • Approximation for BK X, XJ/, +- , J/l+l- : X,  and J/ rest framescoincide, angular distr. are predicted in the joint ref. frame (Rosner PRD 70, 094023 (2004)) • Rosner’s coordinate system: x-axis is negative of K direction in X rest frame, x-y plane defined by + and K, z-axis completes right handed system • Each JPC hypothesis examined using the most distinctive angular distr. • 0-+ hypothesis  and J/ in a P-wave: d2N/d(cos) d(cos)  sin2 sin2 hep-ex/0505038 Poor fit to cos distribution evidence against 0-+ Jolanta Brodzicka, INP Kraków New Resonances ICFP 2005

  7. MC expectation 2/d.o.f=31/9 2/d.o.f=11/9 |cosl| |cosl| 2/d.o.f=5/9 |cos| Constraints on JPC of X(3872) • 0++ hypothesis: ( and J/ in S/D-wave) • Predicted: dN/d(cosl) sin2l Poor agreement 0++ ruled out • 1++ hypothesis: ( and J/ in S/D-wave) • Predicted: d2N/d(cosl) d(cos) sin2l sin2 Good agreement 1++ favored Jolanta Brodzicka, INP Kraków New Resonances ICFP 2005

  8. threshold effect? new charmonium state? • cc at this mass dominantly DD(*) • cc-g hybrid? (predicted states with properies similar to Y(3940), but M>4GeV) Observation of Y(3940)   J/ PRL 94, 182002 • X(3872) +- J/ encouraged further studies of h+J/ systems: J/ system in BK J/, +-0 • BKJ/ signal yield determined in M(J/) bins by fits to Mbc distr. N=58±11 (8.1) M= 3943±11±13 MeV =87±22±26 MeV Strong near-threshold enhancement in M(J/) @ 3.94GeV BF(BKY)BF(YJ/) =7.1 ±1.3 ±3.110-5 Jolanta Brodzicka, INP Kraków New Resonances ICFP 2005

  9. Double cc production in e+e- annihilation (J/ + c c ’c): large cross sections, difficult to understand by theory • Searching region extended above DD thr. with new data (350fb-1) X(3940) ’c c c DD threshold Observation of X(3940) in e+e-J/ X PRL 89, 142001 Recoil mass against J/ studied: • New peak observed in Mrecoil(J/) @ 3.94GeV hep-ex/0507019 Fit result: X < 52MeV @ 90%C.L BornBF( X(3940)>2 charged tracks ) =10.6±2.5±2.4 fb (>4 ch.tracks required in analysis and J/ll) Jolanta Brodzicka, INP Kraków New Resonances ICFP 2005

  10. Full reconstruction of e+e-J/X, XD(*)D not practical (low eff.)  one D reconstructed ND*D= 55±18 NDD= 86±17 e+e- J/DD, J/DD* observed • Mrecoil(J/)  M(D*D), M(DD) spectra X(3940)D*D N=24.5 ± 6.9 (5.0) M=3943 ± 6 MeV =15.4 ± 10MeV X(3940)DD N=0.2 +4.4 <8.1 –3.5 BF>2(X(3940)D*D) = 96 +45 ±22 % seems to be dominant decay mode -32 Search for X(3940) D(*)D • Mrecoil(J/D) is studied: the other D(*) seen as peak in Mrecoil(J/D) (D* and D signals well separated) • Mrecoil(J/D) refited to MD or MD* to improve Mrecoil(J/) resolution BF>2(X(3940)DD) < 41% @90% C.L. (conservative) Jolanta Brodzicka, INP Kraków New Resonances ICFP 2005

  11. NJ/= 2.2 +4.5 –3.7 NX = 1.9 +3.2 < 7.4 @90% C.L. BF( X(3940)J/ ) < 26% @90% C.L. –2.4 Are X(3940) and Y(3940) the same particle? • Search for X(3940)   J/ • J/  reconstructed in e+e-J/ J/ • M( J/) vs. Mrecoil( J/) studied to look for X(3940) for M(J/) – MX< 40 MeV Signal region for e+e-J/X, X J/ • X(3940) does not decay into J/  for Mrecoil (J/) – MJ/<100 MeV Jolanta Brodzicka, INP Kraków New Resonances ICFP 2005

  12. Observation of Z(3930) in   DD • Motivation: study  production of high mass cc states decaying into DD • Known 2S charmonia ’ and ’c: M<MDD • 23PJ(’cJ) predicted at ~3.9-4.0 GeV and to decay mainly to DD • untagged  in e+e-e+e-DD • Pt(DD)<0.05GeV ine+e- cms  enhances exclusive  DD production New peak in M(DD)@3.93 GeV Pt(DD) distr. for Z(3930) peak agrees with MC for   DD MC expectation hep-ex/0507033 N=4111 (5.5) M=393142 MeV =2083 MeV (2J+1) BF (ZDD) =1.13±0.30±0.18 keV Jolanta Brodzicka, INP Kraków New Resonances ICFP 2005

  13. for 3.91< M(DD) <3.95 GeV Spin-2 dN/d(cos *)~sin4* 2/d.o.f=7/9 Spin-0 flat distr. 2/d.o.f=32/9 Z(3930) angular distribution • Study of the D angle relative to the beam axis in  cms  Events from the 3.93 GeVpeak tend to concentrate at small |cos * values Data prefer J=2 assignment • Z(3930) is ’c2 23P2 charmonium state Jolanta Brodzicka, INP Kraków New Resonances ICFP 2005

  14. Summary Belle at KEK-B: the goldmine for spectroscopy This year: • new decay modes of X(3872), JPC=1++ established (’c1 unlikely) • new X(3940) in double charm production (c(3S)?) • Z(3930) in  process (’c2 likely) Earlier observations: • ’c(2S) • D** (+DsJ) • c(2800) isotriplet • Y(3940) (cc g hybrid?) Jolanta Brodzicka, INP Kraków New Resonances ICFP 2005

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