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Recent results of ψ' decays at BES

Recent results of ψ' decays at BES. WANG Zheng CCAST, Beijing,10049 China For BES Collaboration. The International Conference on QCD and Hadronic Physics Jun. 16-20, 2005, Peking University, Beijing, China. Outline. BES results of Ψ´ hadronic final state decays .

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Recent results of ψ' decays at BES

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  1. Recent results of ψ' decays at BES WANG Zheng CCAST, Beijing,10049 China For BES Collaboration. The International Conference on QCD and Hadronic Physics Jun. 16-20, 2005, Peking University, Beijing, China

  2. Outline • BES results of Ψ´ hadronic final state decays. • Ψ´ hadronic and EM transition measurement. • Summary. • VP mode:  , K*+K-+c.c., K*0K0+c.c., 0,… • PP mode: KSKL • 3 or-multi-body: pp0, pp, +-0,3(+-), … (2S)(, η or 2 photons) +J/

  3. BES Detector and the data 14 Million Tracking: Main Drift Chamber Photon ID: BSC 6.42pb-1 continuum data (Ecm=3.65GeV) to estimate the continuum bg. Hadron ID: MDC(dE/dx)+TOF

  4. From “12% rule” to “ρπ puzzle” J/ and ’ hadronic decays proceed via 3 gluons or a virtual photon, neglect the difference of S at J/ and ’ , the ratio of ’ and J/ BRs is : Qh= ≈12% MARK-II • Violation was observed by MARK-II , Confirmed by BESI at higher sensitivity. K*K ρπ

  5. Theoretical explanations Many theoretic attempts, using, for instance, intermediate vector glueballs, hadronic form factors, final states interactions, etc. try to solve the puzzle. A recent study originally proposed by J.L. Rosner shows that the S- and D-wave mixing model probably gives a unified explanation for 12% rule violation decays. (PRD64, 094002 (2001)) <f |> = <f| 23S1> cos – <f| 13D1>sin, <f |  >= <f | 23S1> sin + <f| 13D1>cos. (=12º) “12%” rule: |<f|J/>|2/|<f|23S1>|2 = ee(J/)/ee(23S1)  <f| 23S1> (Rosner’s assumption) This mode developed by BES members by adding interference between continuum and ψ" amplitudes, may possibly explain the 12% rule, and can give some prediction for " decays. (Wang, Yuan and Mo:PLB574,41(2003)) Observed Cross Section of Ψ"ρπ MK3 UL (<6.3pb) Favors φ=﹣90° Therefore measurements at J/, , and  can be used to test the model !

  6. BES results of ψ´ VP Decays

  7. ’ + - 0 Event Selection • Two charged tracks with net charge zero; • |cosθ|<0.80 for all tracks, TOF and dE/dx for part ID; • photon ID: E>0.08GeV, far from charged tracks • Remove ψ’π﹢π﹣J/ψ and Bhabha background; • Kinematic fit (4C), Prob>0.01. Bhabha + - 0 Prob_4C hep-ex/0408047 PLB in Press

  8. PWA of Ψˊ→π+π-π0 ΨˊData Continuum Data (26019) 0s (104) 0s Two photons invariant mass Number of ψ(2S)+ - 0: 22923 Continuum contributions are subtracted incoherently in 3πevents. hep-ex/0408047 PLB in Press

  9. PWA of Ψˊ→π+π-π0 Ψ(2S) peak 13% bkg Ψ(2S) peak 13% bkg 3.65 GeV 42% bkg ρ(770) band J/Ψ→μμ decay veto J/Ψ Very different from J/Ψ3! Need PWA to extract ρπ signal!

  10. PWA Ψˊ→π+π-π0 • ML fit for the Dalitz plot. • Helicity amplitude: • ρ and its excited states. • ρ was described by Gounaris-Sakurai(GS) parameter. Ψˊ π ρ π π

  11. PWA of Ψˊ→π+π-π0 3π: (770)π: (2150) π = 1:0.28±0.03:1.07±0.09 in Ψˊ→3π process. (770)π, (2150)π are dominant.

  12. PWA of Ψˊ→π+π-π0 hep-ex/0408047 PLB in Press

  13. K*(892)K+c.c. KS K+-+c.c. K* B.G. K*2(1430) K*0 K*0 65.6±9.0 evts, 11σ Br0=(13.3±2.7 ±1.7)10–5 K*2(1430) K* Br± =(2.9±1.7 ±0.4)10–5 B.G. 9.6±4.2 evts, 3.5σ First observation! Large Isospin violation! PLB614, 37 (2005)

  14. K*(892)K+c.c. KS K+-+c.c. PLB614, 37 (2005) CONTINUUM CONTRIBUTION SUBTRACTED INCOHERENTLY! 12% rule Suppressed !! The isospin violation observed here also indicates EM decay , continuum contribution and their interference are important in Ψ´ physics.!

  15. Ψ´η, η’,η,η’ η’ η’ π0, η η’ η’ η PRD70 (2004) 112003

  16. ψ ´ η, η’,η,η’ No event observed in continuum data sample for such decay modes! Subtraction of zero event continuum background are also taken into consideration in systematic error analysis! ! PRD70 (2004) 112003

  17. EM Process: 0,,ˊ at Ecm=3650,3686,3773 MeV ForEMprocesses at continuum e+e- (VP) 0 , , ˊ Pvp(S)=q3vp/3 ; q3vp – momentum of V or P ; Fvp(s) – form factor . ForEMprocesses at Ψˊ (VP) 0, , ’ =R+cont(INT  0, P.Wang et al, PL B593 (2004) 89 ) interference BRs (M Ψ(2S)) & Fvp obtained simultaneously. EM process, hep-ex/0410031

  18. EM Process: 0, , ˊ at Ecm=3650, 3686, 3773 MeV ωπ0 ρη ρηˊ Ecm=3650 MeVL = 6.42 pb-1 Ecm=3686 MeV N Ψ(2S) = 14M Ecm=3773 MeVL = 17.3 pb-1

  19. 0 form factor Curve A -- J.Gerard, PLB425(1998)365 F(0) ~ 1/s Curve B –V.Chernyak, hep-ph/9906387 F(0) ~ 1/s2

  20. 0,,’ at Ecm=3.65, 3.686,3.773 GeV Born order cross section, from factor, and branching fraction measurement of the VP isospin violating decays. PRD70 (2004) 112007

  21. Test of pQCD 12% Rule 12% Rule PQCD 12% Rule test using BESII Ψˊ→VP results

  22. ψ"ρπ, testing the S-D mixing mode In S-D mixing model by Rosner, ψ(3770)ρπ process is predicted to be enhanced! Considering the continuum amplitude, the observed cross section and BR of ρπ decay at ψ(3770) are predicted in Wang, Yuan and Mo:PLB574,41(2003). So the measurement ofψ(3770)ρπ is a test of the S-D mixing mode for the explanation of the “ρπ puzzle” . BESIII or CLEOc BES preliminary BESII  data: 17.3 pb-1 Model prediction ρπ signal is missing atψ" because of destructive interference between the continuum amplitude and ψ(3770) amplitude(φ=-90o). That indicateBR(ψ(3770)ρπ ) at 10-4 level.  is the relative phase between  strong and EM decays.

  23. BES results of ψ´ PP decay, multi-body Decay

  24. Study of ψ´p π0(η) 0: 25618 : 44.8 8.7 PRD71, 072006 (2005)

  25. ψ´ Multi-body decays hep-ex/0503040, BES preliminary

  26. ´ (J/ψ) KS KL 58MJ/ψ 14M ψ(2S) signal Bkg MC Ks mass sidebands PRL 92, 052001 (2004) PRD 69, 012003 (2004)

  27. ' , J/  KS KL B ’ Ks KL= (5.24± 0.47± 0.48 )  10 – 5 B J/ Ks KL = (1.82 ± 0.04± 0.13 )  10 – 4 ’ decay enhanced more than 4 σ

  28. BES results of ψ´ hadronic and EM transitions

  29. ´ strong and EM transition(motivation) Prediction of transition amplitude ratio byPCAC (Partially Conserved Axial-Vector Currents) theory. • Old measurements do not agree well. • B(’  oJ/) is measured with low precision: • (23 evts at CBAL, 7 evts at MRK2). • Meanwhile, results of high statistics measurements can test theoretical predictions by PCAC(Partially Conserved Axial-Vector Currents),QCD multipole expansion, i.e. for charmonium hadronic transition amplitudes. • Inclusive Ψ´X+JΨ measurement is also useful to test “12% rule”. Prediction of transition amplitude ratio byQCD multipole expansiontheory.

  30. ´ strong and EM transition Measure: '  oJ/,J/ , ππJ/ ' cJ  J/ (J=1,2) J/ are reconstructed by two leptons. Charmonium System under DDbar threshold. Phys.Rev.D70:012006,2004

  31. ' J/ J/ cJ  J/ Take + final state as an example MC 0J/ J/e+e or +, 5C (J/ mass) kinematic fit is applied! BKG from 00J/

  32. ' J/  (2S) →cJ→ J/ e+e + e+e Two photons Inv. Mass distribution for(2S) → 0J/ + e+e + Two photons Inv. Mass distribution for(2S) → J/ Inv. Mass distribution of  J/

  33. ' J/ PDG04 2.67 ± 0.15 1.30 ± 0.08

  34. ' J/ Phys.Rev.D70:012006,2004 BES most accurate c1 J/ c2 oJ/ BES BES measures the BRs with high precision!

  35. Discussion ' J/ BES (+PDG for ): R= 0.048 ± 0.007 R' < 0.0098 R" < 0.0065 • PCAC prediction R=0.0162 is smaller than our measurement by a factor of 3. • [G. A. Miller, Phys. Rep. 194,1(1990)]: • Consistent with the prediction byQCD Multipole expansion & BTG potential model • [Y. P. Kuang, PRD24, 2874(1981), ibid. 37, 1210(1988)] R' = 0.0025 R" = 0.0013 Phys.Rev.D70:012006,2004

  36. ' XJ/ BES 4M Ψ(2S) data Method – J/ signal is reconstructed by J/+ Select muons. 1 C fit to mJ/ Obtained the mass recoiling against the J/Ψ (mX) from energy and momentum conservation. The exclusive BRs are determined from fits mass distribution of X. At last, report the ratios of the studied BRs to that for B(’  π+π-J/ ) pX p μ+ p μ- pJ/ PRD70,012003(2004)

  37. ' XJ/ J/ peak • Fit distribution: • background (mμμ< 3.4) • 1307 events • signal 44498 events Background e+ e-   μ+μ- and e+ e-  ’   μ+ μ-

  38. ' XJ/ fit result To separate ’  00J/ and +J/, plot mX for no extra charged tracks and for extra charged tracks. Fit two simultaneously with component shapes. 2 < 7 no extra charged track extra charged track + 00 η c2 c1 η backgrd Mx distribution obtained from the mass recoiling against J/Ψ

  39. ' XJ/ The ratios of the studied BRs to that for B(’  π+π-J/ ), Sosystematic errors with same source between two BRs are cancelled. measured BESI – 4 million (2S) events. Phys.Rev.D70:012003,2004

  40. Summary • 10 ’ VP decay channels are measured, many other multi-body decays are studied. “12% rule” is tested extensively. Observation of ρπ and K*K. • S- D-wave charmonia mixing model is tested in ρπdecay mode, data agree with prediction well. This may supply a way to explain the 12% rule violation. ´ρπ, ’’ρπ,. • Ψ´EM and hadronic transition are studied. BRs are measured Thanks a lot !

  41. backup BES results of ΧcJ parameters and decays measurement.

  42. ΧcJparameters,Inclusive e+e- spectrum At BES, the momentum resolution for charged tracks in MDC (σp/p=1.7%/1+p2) is much better than its energy resolution for the photons in BSC(E/E= 22 %), So BES use a method of gamma c0 conersion in detector (e+e- )to obtain the inclusive gamma spectrum in Ψ´ decays. data c1 c2 Mass (MeV): c0=3414.21±0.39±0.27 c1=3510.30±0.14±0.16 c2=3555.70±0.59±0.39 Bkg subtract Width (MeV): c0=12.6±1.6±1.0 c1=1.39±0.40±0.77 Paper Accepted hep-ex/0502031 Invariant mass of two electrons converted from photons.

  43. Results of Hadronic decays of cJ Many measurements are first observations! Useful for understanding the decay dynamics and testing the new QCD approach including the effect of the Color Octet Mechanism(COM, …). Hep-ex/0410028 PRD70, 092002 (2004) PRD70, 092003 (2004)

  44. Search for muti-quark state using Ψ´ data

  45. Search for Ψ´(J/Ψ)Θ decays ’ J/ Not observe pentaquark in BES data PRD70, 012004 (2004)

  46. Dalitz analyses for ’pp0, pp R(2000) PRD71, 072006 (2005) MC Ppbar inv. Mass of selected ppπ0(η) events.(Enhancements around 2 GeV/c2 in two channels, not same since they have different isospin) N* All the signals are not significant, more statistical is needed. N*(1440, 1520,1535), no clear N*(2065)? MC J/ bkg Pπ (pη) inv. Mass after removing Ψ´J/Ψ+X bg. PRD71, 072006 (2005)

  47. σ Search in Ψ´π+π-J/Ψ

  48. σ search in ’+-J/ ~ 40,000 evts BES Preliminary Pole position is consistent with the PWA result of J/Ψωπ+π- (54139)-i(25242) MeV Phys.Lett.B598:149-158,2004

  49. VP mode BESII .VS. CLEO-c • Most channels BRs are consistent. • BES BR()>CLEO • by ~ 3 because the different treatment of continuum BG. and the interference between ρ(770) and its excited state in PWA. • BR(K*0K0) are deviated (different treatment of the continuum contribution) Upper limit @90％ C.L. IHEP Zheng Wang

  50. ’ VP: comparison with CLEOc results • Most channel consistent. • (770) • BES > CLEO ( ~ 2.5) • fit vs cut and destructive • interference. CLEOc BESII

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