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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 X(3872) properties Y(3940), a hybrid state? X(3940), a new charmonium state? Z(3930), an excited charmonium state? Summary. 253fb -1 N=49.1  8.4.

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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 • X(3872) properties • Y(3940), a hybrid state? • X(3940), a new charmonium state? • Z(3930), an excited charmonium state? • Summary

  2. 253fb-1 N=49.18.4 X+- J/ Intriguing X(3872) • X(3872)+- J/ discovered by Belle in 2003 in B+K++- J/ decay M= 3872.0 ± 0.6 ± 0.5 MeV <2.3 MeV @90% C.L. BF(BK X)BF( X+-J/)=1.31±0.24±0.13 10-5 • Confirmed by other experiments (BaBar, D0, CDF) and included in PDG2005 M(+-J/) • M and  do not fit well any potential model charmonium states • M(+-) peaks at kinematic limit ((770)-like) X(3872) 0J/ is isospin violating decay • MX ~ MD*0+ MD0  speculation that X might be a molecular D*0D0 bound state • JPC= 1++ favored by some models (Swanson, PLB 588, 189(2004)) • Expected admixture of (782)J/ and a small (770)J/ component in addition to D*0D0 Jolanta Brodzicka, INP Kraków New Resonances ICFP 2005

  3. X(3872) region N=13.6±4.4 (4.0) BF(BK X)BF(XJ/)=1.8±0.6±0.110-6 M(J/) (XJ/)/(X+-J/) = 0.14±0.05 Evidence for X(3872) J/ • If X(3872)  J/  C=+1 for X(3872)  search for BK X(3872), X(3872) J/ decay • Mbc distributions in M(J/) bins  significant B signal only for M(J/)~MX(3872) • Fit Mbc in M(J/) bins  BK J/ signal yield versus M(J/)  CX(3872) =+1 established Jolanta Brodzicka, INP Kraków New Resonances ICFP 2005

  4. Virtual (782)? N=12.4±4.1 (4.3) M(+-0 ) X(3872) J/ sub-threshold decay • Kinematical limit for X(3872) J/ is 7.5MeV below M  via virtual  • Search for BK X(3872), X(3872) J/, +-0 decay • BK +-0 J/candidates selected in E-Mbc signal region X(3872) +-0 J/ selected:|M(3J/) – 3872|<16.5 MeV • Mbcvs. E distributions fitted in bins of M(+-0 )  B signal yield versus M(+-0 ) • Significant B signal only for (782) region M(+-0 )>750 MeV • Background: 2.1±1.0 (from BK J/ and non-resonant BK +-0 J/) • Strong support for molecular D*0D0 interptetation • Further evidence of C=+1 for X(3872) BF(X +-0 J/)/BF( X +-J/) =1.0 ±0.4 ±0.3  large isospin violation! Jolanta Brodzicka, INP Kraków New Resonances ICFP 2005

  5. S-wave 2/d.o.f=43/39 Favored by 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(+-) • For C=+1 states +- J/ final state is primarily J/, • J++ :  and J/ in a relative 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  PX(3872) =+1 is favored M(+-) Preliminary • X(3872) D0D00 observation • BKD0D00(KD0 D*0)candidates selected using E-Mbc • Enhancement in M(D0D00)MX observed • It is difficult to distinguish D0D00andD0 D*0 BF(BK X)BF(XDD)=1.6±0.4±0.310-4 • XDD makes J2 unlikely, for J=2 D-wave required, 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| Constraints on JPC of X(3872) II • Two-body decay BKX(3872)  constraints on X spin and K-X relative angular momentum • Full angular analysis limited by low statistic (NX50 events) • 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 Rosner PRD 70, 094023 (2004) • Each JPC hypothesis is examined using most distinctive angular distribution • 0-+ hypothesis: and J/ in a P-wave • Predicted angular distribution: d2N/d(cos) d(cos)  sin2 sin2 (in the limit where X,  and J/ rest frames coincide) 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) III • 0++ hypothesis:  and J/ in relative S- or D-wave (D-wave disfavored by M(+-) and suppressed by phase space) • Predicted angular distribution: dN/d(cosl) sin2l • 1++ hypothesis:  and J/ in relative S-/D-wave • d2N/d(cosl) d(cos) sin2l sin2 Poor agreement  0++ ruled out Good agreement for both distr. 1++ favored Jolanta Brodzicka, INP Kraków New Resonances ICFP 2005

  8. N=58±11 (8.1) M= 3943±11±13 MeV =87±22±26 MeV Observation of Y(3940)   J/ • Discovery of X(3872) encouraged further studies of h+J/ systems • BK  J/, +-0 candidates selected • B signal yield determine in M(J/) bins by performing fits to Mbc distributions • Strong near-threshold enhancement in M(J/) @ 3.94GeV BF(BK Y)BF(YJ/)=7.1 ±1.3 ±3.110-5 • Is Y(3940) threshold effect or new charmonium state? • Charmonium meson with this mass would dominantly decay to DD(*) • Y(3940) properties are similar to those predicted for some of the cc-gluon hybrid states Jolanta Brodzicka, INP Kraków New Resonances ICFP 2005

  9. X(3940) ’c c c DD threshold Observation of X(3940) in e+e-J/ X annihilation • Double charmonium production in e+e- annihilation (J/ + c c ’c): large cross sections, difficult to understand within NRQCD  cc production in different processes not completely understood  theoretical interest renewed • Searching region extended above DD threshold with new data (350fb-1) • Spectrum of a J/ recoil mass studied • New peak observed in Mrecoil(J/) @ 3.94GeV=39±29MeV Fit result: BornBF( X(3940)>2 charged tracks ) =10.6±2.5±2.4 fb Jolanta Brodzicka, INP Kraków New Resonances ICFP 2005

  10. ND*D=55±18 NDD=86±17 X(3940)DD N=0.2 +4.4 <8.1 –3.5 BF(X(3940)D*D) = 96 +45 ±22 % dominant decay mode -32 Search for X(3940) D(*)D • Full reconstruction of e+e-J/X, XD(*)D not practical • To increase efficiency only one D reconstructed • Spectrum of Mrecoil(J/D) is studied, other D(*) seen as peak in Mrecoil(J/D) (D* and D well separated) • Observed processes e+e-J/DD, J/DD* • Mrecoil(J/D) refited to MD or MD* to improve Mrecoil(J/) resolution • Search for XD(*)D in Mrecoil(J/) M(D(*)D) spectra X(3940)D*D N=24.5 ± 6.9 (5.0) M=3943 ± 6 MeV =15.4 ± 10 MeV BF(X(3940)DD) < 41% @90% C.L. 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 from e+e-J/ J/  final state • M(J/ ) vs. Mrecoil(J/ ) studied to look for X(3940) for M(J/ ) – MX(3940) < 40 MeV Signal region for e+e-J/ X(3940), X(3940)  J/  for Mrecoil (J/ ) – MJ/<100 MeV Jolanta Brodzicka, INP Kraków New Resonances ICFP 2005

  12. Observation of Z(3930) in   DD N=4111 (5.5) M=393142 MeV =2083 MeV MC expectation • Motivation: study  production of high mass cc states decaying into DD • Known radially excited 2S charmonium states ’ and ’c: M<MDD • 23PJ(’cJ) predicted to lie: 3.9-4.0 GeVand to decay mainly to DD • Search for cc statesproduced via   DD process by studying untagged mode e+e-e+e-DD • Pt(DD)<0.05GeV ine+e- cms  it restricts  virtualities and enhances exclusive   DD production • New peak observed in M(DD)@ 3.93 GeV • Pt(DD) distribution for Z(3930) region agrees with MC for exclusive two-photon DD production (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/c2 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 angle of D relative to the beam axis in the  cms frame • Events from the 3.93 GeVpeak tend to concentrate at small |cos * values Data prefer a J=2 assignment  Z(3930) is ’c2 the 23P2 charmonium state Jolanta Brodzicka, INP Kraków New Resonances ICFP 2005

  14. Summary Belle found: • More informations to explain X(3872) properties • X(3872) quantum numbers: JPC=1++ • New charmonium state X(3940) (c(3S)?) in double charmonium production • Z(3930) in  process, Z(3930) = ’c2 Jolanta Brodzicka, INP Kraków New Resonances ICFP 2005

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