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 Decays at CLEO

 Decays at CLEO. Steve Blusk Syracuse University for the CLEO Collaboration. Preview Introduction Measurements of B (  (nS)  m + m - ) Electric Dipole Transitions  (1S)  ( c c ) + X Summary. ICHEP’04, Beijing, China Aug 16-22,2004. CLEO III. Bottomonium.

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 Decays at CLEO

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  1.  Decays at CLEO Steve BluskSyracuse Universityfor the CLEO Collaboration Preview • Introduction • Measurements of B((nS)  m+m- ) • Electric Dipole Transitions • (1S)  ( c c ) + X • Summary ICHEP’04, Beijing, China Aug 16-22,2004

  2. CLEO III Bottomonium n2S+1LJ J=L+S • 1-- (bb) states couple to virtual photon • (1S)- (3S) too light to form B mesons ggg and qq decays dominant, but suppressed.  States are narrow !  EM and hadronic transitions to lower-lying bb states competitive • (4S)BB; Weak Int. Physics Spin-orbit3PJ3P0,1,2 Hyperfine(spin-spin) splitting JPC Photon Transitions E1: |DL|=1, DS=0: M1: DL=0, |DS|=1:  GE1 >> GM1

  3. Detector & Data Samples Analyses presented here makeextensive use of the excellent CsIcalorimeter, tracking and muonsystems 106 (1S) CsI: 6144 crystals (barrel only): sE/E ~ 4% at 100 MeV ~2.5% at 1 GeV Tracking (2S) (3S)

  4. Measurement of B((nS)m+m- ) ICHEP ABS10-0774 • Goal: Extract Gtot.of (nS) . • Gtot << dEbeam  cannot be extracted by scanning the resonance. • Use: Gtot= Gee / Bee = Gee / Bmm where Bll=B((nS)m+m-); (assumes lepton universality) • B((nS)m+m- ) also important for (nS) EM & hadronic BF’s. • We actually measure: • Which is related to Bmm by: Background dominated by cascade decays:e.g. (2S) (1S) 00/   (2S) : (2.9±1.5)% (3S) : (2.2±0.7)% • (nS)m+m-Event Selection • Exactly 2 back-to-back oppositely charged muons • < 2 showers with E>50 MeV (2S) Data (nS)m+m- efficiency: (65.2±0.2)% Nsh 2 (2S)m+m- Nsh < 2 • (nS)hadrons Event Selection • >2 charged tracks • For Ntrk<5: (Ecc> 0.15Ecm) & (Ecc<0.75Ecm or Eshmax<Ebeam) • Evisible > 0.2Ecm (2S)(1S)X,(1S)m+m- (nS)hadrons efficiency: (97-98)% Mmm/Ebeam

  5. Results (1S) mm in goodagreement with previousmeasurements(2S), (3S) mmsignificantly larger than current world average values B(%) B(%) B(%)

  6. C. Davies, et al, PRL 92. 022001 (2004) Electromagnetic Transitions • Aim is to get precision measurements of masses and transition rates.Tests of LQCD & effective theories, such as potential models or NRQCD. • We present results on Inclusive Analyses of E1 transitions: • (2S)gcbJ(1P) • (3S)gcbJ(1,2P) • Can be used to extract E1 matrix elements and extract relative importance ofspin-orbit and tensor interactions.

  7. e+e-m+m- hadrons g Inclusive(2S)gcbJ(1P) g hadrons Raw hadrons Preliminary Backgroundsubtracted Dominant Systematics B: Shower Simulation & Fitting Eg: Calorimeter calibration

  8. g Inclusive(3S)gcbJ(1,2P) (3S)gcbJ(2P) (3S)gcbJ(1P) ¡(3S)  b(1P0)  ¡(3S)  b(1P2)  + ¡(3S)  b(1P1)  + b(1PJ) ¡(1S)  (1DJ)b(1Pj)  Eg(MeV) Preliminary ¡(2S)b(1PJ)  50 100 Eg(MeV) 200

  9. Summary of (2S) gcbJ(1P)Results (Preliminary) (2S)gcb(1P1) (2S)gcb(1P0) (2S)gcb(1P2) Eg B Gives quantitative information on the relativeimportance of spin-orbit & tensor forces

  10. Summary of (3S) gcbJ(2P)Results (Preliminary) (3S)gcb(2P1) (3S)gcb(2P0) (3S)gcb(2P2) Eg B

  11. Charmonium Production in (1S) Decay ICHEP ABS10-0773 • History: CDF observes J/y, y(2S) ~10x, 50x too large.  Braaten & Fleming propose color-octet (CO) mechanism; J/y produced perturbatively in CO state and radiates a soft-gluon (non-perturbatively) to become a color-singlet (CS); <ME> fit to data.  Problems though: J/y polarization data from CDF, e+e-J/y+X from BaBar & Belle, J/y at HERA . Suggestion by Cheung, Keung, & Yuan: If CO is important, the glue-rich decays of  should provide an excellent labortatory for studying the role of the CO mechanism in y production.  Distinct signatures in J/y momentum spectrum (peaking near endpoint). Li, Xie & Wang show that the Y(1S)J/y+ccg may also be important (2 charm pairs) Li, Xie & Wang, PLB 482, 65 (2000) Cheung, Keung & Yuan, PRD 54 929 (1996) 5.9x10-4 6.2x10-4 B((1S)J/y+X) Soft Hard Momentum Spectrum Previous CLEO measurement based on ~20 J/ymm events: B=(11±4)x10-4

  12. Data Sample: 21.2x106(1S) decays • Reconstruct J/ym+m-, e+e- • Backgrounds: • Radiative return: suppressed through Ntrk, Egmax, and Pevmiss requirements • Radiative Bhabha (ee only): veto events where either electron can form M(e+e-)<100 MeV. • ggccJ: Negligible after Ntrk and Pevmiss requirements. • e+e-J/y+X continuum: Estimated using U(4S) data and subtracted. • Efficiencies:~40% (~50%) for J/ymm (J/yee); small dependence on momentum, cosq Event Selection & Signals e+e-J/y+X below Y(4S) (1S)J/y+X

  13. (1S)J/y+X Continuum Background BaBar s(e+e-J/y+X)=1.9±0.2(stat) pb BaBar: s(e+e-J/y+X)=2.52±0.21±0.21 pb, PRL87, 162002 (2001) Belle: s(e+e-J/y+X)=1.47±0.10±0.13 pb, PRL88, 052001 (2002) B((1S)J/y+X)=(6.4±0.4±0.6)x10-4 Normalization to (1S) Data * Luminosity ratio * Phase space ratio: 0.78±0.13 • Spectrum much softer than CO prediction • Somewhat softer than CS prediction • Very different from continuum

  14. First Observations/Evidence (1S)ccJ+X (1S)y(2S)+X (4S) Continuum CO & CS both predict ~20% cc1, cc2 BF’s ~2x CO prediction

  15. Summary • CLEO has the world’s largest sample of (1S),  (2S), and (3S) data sets Precision measurements in (bb) spectroscopy (rates, masses) provides • a unique laboratory for probing QCD. •  Glue-rich environment is ideal for studying color-octet predictionsRecent work also includes: •  Searches/limits for M1 transitions (hb) •  First observation of a (1D) state (first new (bb) state in 20 years!) •  Measurements of new hadronic transitions (e.g., cb1,2(2P)w(1S)) •  Searches for anomalous couplings • Many other interesting topics are in the pipeline • Exclusive 2g and 4g transitions in (3S) decays • New measurements of Gee for (1S), (2S), (3S) • (1S,2S,3S)Open Charm • (1S) rp, K*K, etc (“rp puzzle”) • Searches for LFV • …

  16. Backup Slides

  17. The Physics The (1S)- (3S) resonances are the QCD analogy of positronium - bb are bound by the QCD potential: e.g. V(r)= – 4/3 s/r + kr Large b quark mass  (v/c)2 ~ 0.1  non-relativistic to 0th order(In some models, relativistic corrections added to non-relativisticpredictions) In much the same way that positronium allowed for a greater understanding of QED, the masses, splittings between states and the transition rates provide input into understanding QCD. Tests of lattice QCD Important for flavor physics ! Test of effective theories, such as QCD potential models Coulomb-like behaviorfrom 1-g exchange Long distancebehavior, confiningk~1 GeV/fm

  18. y  Electric Dipole Transitions In the non-relativistic limit, the E1 matrix element is spin independent. Using: E1=B(niSnfP)tot((nS)) Uses newCLEO Gtotvalues We can extract After normalizing out the (2J+1)E3 between different J’s, we obtain: Comparison with various models o = predictions (non-relativistic)▲ = spin-averaged predictions (relativistic) • In NR bb system, (v/c)2~ 0.1  expect ratios ~ 1 • NR corrections O(<20%) for J=0 • Also shown are (cc), which show sizeabledifferences (v/c)2~0.3; mixing between23S1and 13D1 states may also contribute. time • Relativistic corrections needed for (cc) • In (bb) system, NR calculations in reasonable agreement with data.

  19. Spin-Orbit & Tensor Interactions Responsible for splitting the P states 3PJ where Can express:MJ=2 = Mcog + aLS - 0.4aT MJ=1 = Mcog - aLS + 2aT MJ=0 = Mcog - 2aLS - 4aT Spin-Orbit Coeff. Tensor Coeff. V0= static potential; V2,3= spin-dependent potentials(both model-dependent) Data on mass-splittings can be used to extract aLS and aT, • Experimentally, the mass splittings are most precisely determined using Our results indicate that there is no difference between the different radial excitations of the P waves in (bb) system.

  20. Search for hb in (3S)  b(1S) and (2S)  b(1S) ¡(2S)  b(1S)  ¡(3S)  b(1S)  g U(2S) Data U(3S) Data Hindered (ninf) M1 transition suppressed by 1/mb2 Large differences amongmodels b(1PJ)  ¡(1S)  b(2PJ)  ¡(1S)  ¡(2S)  b(1S)  ¡(3S)  b(1S)  ¡(3S)  b(2S) 

  21. CUSBII(PRD46,1928(1992)) vs CLEOIII £(3S)~200/pb£(3S)~1300/pb ~10%(poor segmentation of calorimeter)~60% Also it seems that they had worse energy resolution. We are very surprised that they claimed comparable accuracyto ours. ¡(3S)  b(2PJ) 

  22. e+e-J/y+X using on Y(4S) Data, pJ/y>2 GeV

  23. Y(1S) & Y(4S) Overlayed

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