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

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

Jolanta Brodzicka, INP Kraków New Resonances ICFP 2005 Evidence for X(3872)  J/   If X(3872)   J/   C=+1 for X(3872)  search for B  KX, X  J/   search for B  KX, X  J/   M bc distributions in M(  J/  ) bins  B  K  J/  signal seen only for  B  K  J/  signal seen only for M(  J/  )~M X(3872) M(  J/  )~M X(3872)  Fit M bc in M(  J/  ) bins  B  K  J/  signal yield vs M(  J/  )  B  K  J/  signal yield vs M(  J/  ) BF (B  KX)  BF (X  J/  )=1.8±0.6±0.1   C X(3872) =+1 established X(3872) region N=13.6±4.4 (4.0  ) M(  J/  ) Theory expects: ~40 for Theory expects: ~40 for X(3872)=  ’ c1 (2 3 P 1 ) hep-ex/  (X  J/  )  (X  +  - J/  ) = 0.14±0.05

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

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

Jolanta Brodzicka, INP Kraków New Resonances ICFP 2005 Constraining J PC [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 frames coincide, X,  and J/  rest frames coincide, angular distr. are predicted in the angular distr. are predicted in the joint ref. frame ( Rosner PRD 70, (2004)) joint ref. frame ( Rosner PRD 70, (2004))  Rosner’s coordinate system: x-axis is negative of K direction in X rest frame, x-axis is negative of K direction in X rest frame, x-y plane defined by  + and K, z-axis completes x-y plane defined by  + and K, z-axis completes right handed system right handed system  Each J PC hypothesis examined using the most distinctive angular distr. the most distinctive angular distr.  hypothesis  and J/  in a P-wave :  and J/  in a P-wave : d 2 N/d(cos  ) d(cos  )  sin 2  sin 2  d 2 N/d(cos  ) d(cos  )  sin 2  sin 2  Poor fit to cos  distribution  evidence against  2/d.o.f=18/9  2/d.o.f=34/9 MCexpectations |cos  | |cos  | hep-ex/

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

Jolanta Brodzicka, INP Kraków New Resonances ICFP 2005 Observation of Y(3940)   J/  N=58±11 (8.1  ) M= 3943±11±13 MeV  =87±22±26 MeV BF (B  KY)  BF (Y  J/  ) =7.1 ±1.3 ±3.1  Strong near-threshold enhancement in M(  J/  3.94GeV  X(3872)  +  - J/  encouraged further studies of h +J/  systems: studies of h +J/  systems:  J/  system in B  K  J/ ,  +  -  0  J/  system in B  K  J/ ,  +  -  0  B  K  J/  signal yield determined in M(  J/  ) bins by fits to M bc distr.  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) properies similar to Y(3940), but M>4GeV) PRL 94,

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

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

N J/  = –3.7 Jolanta Brodzicka, INP Kraków New Resonances ICFP 2005 Are X(3940) and Y(3940) the same particle?  Search for X(3940)   J/   J/   reconstructed in e + e -  J/  J/   M(  J/  ) vs. M recoil (  J/  ) studied to look for X(3940) for  M(  J/  ) – M X  < 40 MeV for  M recoil (  J/  ) – M J/   <100 MeV Signal region for e + e -  J/  X, X  J/  X  J/  N X = < C.L. BF ( X(3940)  J/   ) < C.L. –2.4  X(3940) does not decay into J/   into J/  

Jolanta Brodzicka, INP Kraków New Resonances ICFP 2005 N=41  11 (5.5  ) M=3931  4  2 MeV  =20  8  3 MeV MCexpectation (2J+1)   BF (Z  DD) =1.13±0.30±0.18 keV Observation of Z(3930) in   DD hep-ex/  Motivation: study  production of high mass cc states decaying into DD cc states decaying into DD  Known 2S charmonia  ’ and  ’ c : M<M DD  2 3 P J (  ’ c J ) predicted at ~ GeV and to decay mainly to DD and to decay mainly to DD  untagged  in e + e -  e + e - DD  P t (DD)<0.05GeV in e + e - cms  enhances exclusive   DD production enhances exclusive   DD production New peak in GeV P t (DD) distr. for Z(3930) peak agrees with MC for   DD

 Study of the D angle relative to the beam axis in  cms Jolanta Brodzicka, INP Kraków New Resonances ICFP 2005 Z(3930) angular distribution for 3.91< M(DD) <3.95 GeV Spin-2 dN/d(cos  *)~sin 4  *  2/d.o.f=7/9 Spin-0 flat distr.  2/d.o.f=32/9 Data prefer J=2 assignment  Z(3930) is  ’ c P 2 charmonium state 2 3 P 2 charmonium state  Events from the 3.93 GeV peak tend to concentrate at small |cos  *  values

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