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					Recent Results of J/ and
    (2S) at BESII

          Zhiyong Wang
           IHEP, Beijing
      for the BES Collaboration
      Rencontres de Moriond 2007
QCD and High Energy Hadronic Interactions
     La Thuile, Italy, 10 – 24, March
                 Outline
• J/ results
  – Wide resonance X(1580).
  – Threshold enhancement in J/
  – ,  invisible
• (2S) results
  –   Hadronic decay
  –   Radiative decay
  –   (2S)+
  –   cJ decay
                    Moriond QCD ,2007   2
                      Data samples
60                                   30

50                                   25
                                                                               28M
40        J/                        20         (2S)
30
                                                                        14M
                                     15

20                                   10
                                                                 4M
10                                   5

0                                    0
     MarkIII    DM2   BESI   BESII        MKI   MKII   MKIII   CBAL   BESI   BESII CLEOc

                         6.42 pb-1 continuum data at
                      Ecm=3.65 GeV for background study.
                             Moriond QCD ,2007                                    3
J/ results



   Moriond QCD ,2007   4
             New Observations at BESII

  In past three years, a number of new structures
  were observed at BESII
• A possible p p bound state:   p p mass threshold
  enhancement in J /   p p and new observation of
  X(1835) in J /   ' .

• p  mass threshold enhancement in          J /  pK  

• K   mass threshold enhancement in        J /  pK  

In this talk, I will report two new structures 
                         Moriond QCD ,2007                   5
Observation of X(1580) in J/  K+K- 0


                                                                          X (1580)



                                                                     0
              X (1580)
                                                                                     K * (1410) 
                                                                                      K * (890) 



                                     Background
     i                     i
M                49  98         22  64
         (157655 91 )  (818 23 133 ) MeV/c 2
                               
     2                     2
                  J PC  1 
Br( J /  X 0 )  Br( X  K  K  )  (8.5  0.6 3..6 )  10 4
                                                   
                                                     27

                                       Moriond QCD ,2007                              6
                                                            PRL97,142002(2006)
 How to understand broad X(1580)?

• Search of a similar structure in J/ 
  KSK  will help to determine its isospin.
• X(1580) could have different nature from
  conventional mesons:
  – Width is much broader than other mesons.
  – Broad width is expected for a multiquark
    state.


                   Moriond QCD ,2007           7
Observation of  mass threshold
   enhancement in J/

 • We studied DOZI process:
   J/    +            +      
                                 
                +-0          K+ K-


                                                       
                                            




                        Moriond QCD ,2007   recoiling against 
                                                              8
Observation of  mass threshold
enhancement in J/

                                                               background
                                  X(1810)
 M2()




               M2()
                                                      M()
              19
  M  1812     26    18 MeV/c   2


    105  20  28 MeV/c         2         Spin-parity favors 0++

  (2.61  0.27  0.65)  10 -4         Phys. Rev. Lett., 96 (2006) 162002


                            Moriond QCD ,2007              9
      Possible interpretations: Multiquark, Hybrid, Glueball
    Searching for /’ Invisible Decays Via J//’
                                                  • Reconstructing K+K ,
                                         Missing
Tag direction                            direction looking at missing momentum of  decays
                                                  • Fast  (1.2 GeV) will help us define the decay
                                                   direction of invisible decay of / (958) .


   No any hit information are required
                                                 Signal MC
   outside of the core of  decays.                                                58 M J/




                                                    missing momentum distribution
     BR(  invisible)
                          1.65 103 @ 90%C.L.
       BR(   )                                            PRL97,202002(2006)
     BR( '  invisible)
                          6.69 102 @ 90%C.L.
       BR( '   )

                                          Moriond QCD ,2007                               10
(2S) results



      Moriond QCD ,2007   11
(2S) hadronic decay
              Bψ' X            Bψ'  e  e 
    Qh                                             12%
             BJ/ψX             BJ/ψe  e 


    3  body : pp , pp , pn  , pn
                            0                              


    Multi  body :    K K            0        




   M. Appelquist and H. D. Politzer, PRL34, 43 (1975)

                       Moriond QCD ,2007                    12
’ 3-body   PRD71,072006(2005); PRD74, 12004 (2006)



                    256±18                  44.8±8.7




                     914±42
   921±40




                 Moriond QCD ,2007             13
’ 3-body        BESII: PRD71, 072006 (2005)
                  BESII: PRD74, 12004 (2006)




             Moriond QCD ,2007                  14
Multi-body ’ decays   BESII, PRD73, 052004 (2006)




                       Moriond QCD ,2007             15
Multi-body ’ decays




            Many intermediate states are
             observed for the first time.


                       Moriond QCD ,2007    16
(2S) radiative decay
  Many channels for (2S)+hadrons with the invariant
    mass of hadrons below 2.9GeV have been studied.




                                           Hep-ex/0612016
                       Moriond QCD ,2007                    17
Search for the strong pp mass threshold
enhancement X(1860) in  (2S )  pp

• A strong pp mass threshold              • No obvious strong pp mass
  enhancement was observed                  threshold enhancement was
  in J /   pp                            observed in  (2S )  pp

               M=1859 +3 +5 MeV/c2                           acceptance
                       10 25
                < 30 MeV/c2 (90% CL)
                                              Fit



                      acceptance

    0           0.1        0.2      0.3       X(1860)
          M(pp)-2mp (GeV)
                                                                         
 B ( J /   X (1860 )  pp )Moriond QCD ,2007 B( (2S )  X (1860) 18pp)
 ~ 7  10 5                                    5.4 106 @ 90% CL
(2S) radiative decay  (2S )     , KK 




                                 PRD74, 072001(2006)
                   Moriond QCD ,2007            19
 ( 2 S )  BB                                     Accepted by PLB

                         B(BBbar)
       Channel  (2S )                   CLEOc                 BES-II
                 pp                    2.870.120.15       3.310.090.23
                                     3.280.230.25       3.390.200.32
                0 0                  2.630.350.21       2.350.360.32
                                   2.380.300.21       3.000.420.31
 According to the hadron helicity conservation, the angular distribution of
 J/,(2S)B8B8 satisfy:
                                     dN
                                             1   cos2 
                                   d cos
                                   ( (2S )  pp)
                         Theo.                             Exp.
                0.58        Claudson et al 0.670.150.04         E835
                0.80             Carimalo      0.850.240.04     BES
                                    Moriond QCD ,2007                         20
(2S) +




     Bree         Br              Br/0.3885
  7.350.18     7.3  0.8        7.93  0.54  0.97
              PRD74, 112003(2006)
                 Moriond QCD ,2007               21
cJ decay

 cJ  , K K , K K K K                              PLB642,197(2006)

 cJ    ,   K K pp
                                             0
                                                 S
                                                     0
                                                     S
                                                             PRD73,052006(2006)

 cJ  K K   c.c.
         0
         S
                            
                                                             PRD74,072001(2006)

 cJ    , a0 (890) ,f 2 (1270)
                    
                                                             PRD74,072001(2006)


Most channels are measured for the first time

                                         Moriond QCD ,2007                22
   cJK+ K K+ K




cJ++ ppbar




 cJ+K,+




       Moriond QCD ,2007   23
               Summary
• A wide 1-- resonance X(1580) is observed in
  J/K+K0 .
• The mass threshold enhancement is observed in
  J/.
• The invisible decay mode is studied for  and 
  Thanks a lot !
  via J//.
• A lot of (2S) radiative and hadronic decay
  channels are measured and the 12% rule are
  tested.
• Many cJ decay modes are observed and most are
  measured for the first time.
                    Moriond QCD ,2007         24

				
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