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

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K X(3872), X(3872)J/ • Mbc distributions in M(J/) bins  B signal 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 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. E fitted in M(+-0 ) bins  B signal yield versus M(+-0 ) • Significant B signal only for M(+-0 )>750 MeV (782) Γ=8.4MeV • 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: X,  and J/ rest frames coincide, 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 signal yield determined in M(J/) bins by fits to Mbc distributions 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