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Bottomonium and Charmonium Results from CLEO

Bottomonium and Charmonium Results from CLEO. The XLI Rencontres de Moriond QCD and High Energy Hadronic Interactions. Outline The CLEO Detector G ee of the K (1S, 2S, 3S) Resonances Measurement of G ee (J/ y ), G tot (J/ y ), G ee [ y (2S)]/ G ee (J/ y )

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Bottomonium and Charmonium Results from CLEO

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  1. Bottomonium and CharmoniumResults from CLEO The XLI Rencontres de Moriond QCD and High Energy Hadronic Interactions Outline • The CLEO Detector • Gee of the K(1S, 2S, 3S) Resonances • Measurement of Gee(J/y), Gtot(J/y), Gee[y(2S)]/Gee(J/y) • Measurement ofs(y(3770)  hadrons) and Gee[y(3770)] • Charmonium Decays of y(4040), y(4160) & U(4260) • Summary T. Ferguson Carnegie Mellon University T. Ferguson

  2. The CLEO/CESR Experiment CESR (Cornell Electron Storage Ring) – Symmetric e+e- collider with capability of running at √s = 3-11 GeV Located at Wilson Synchrotron Laboratory in Ithaca, NY CLEO and CESR have been producing results in B, K, t, and 2-photon physics for almost 30 years T. Ferguson

  3. The CLEO detector Inner Drift Chamber: • 6 stereo layers • 100 mm hit resolution Drift Chamber: • 47 layers • 93% of 4 • Dp/p = 0.6% @ p=1.0 GeV CsI Calorimeter: • 93% of 4 • DE/E = 4% @ E=100 MeV B field 1.0 T Muon Chambers: • 85% of 4 • Identify muons for p > 1 GeV Particle Identification: • RICH detector • dE/dx in drift chamber • Combined e (p or K) > 90% T. Ferguson

  4. Di-electron Widths of K(1S,2S,3S) Resonances Di-electron widths (Gee) are basic parameters of any onium system. Their measurement can also test new unquenched lattice QCD calculations. Precision of previously measured Gee: • 2.2% for K(1S) • 4.2% for K(2S) • 9.4% for K(3S) CESR scanned center-of-mass energies in the vicinity of the K(1S), K(2S) and K(3S) resonances. Data below resonances to constrain backgrounds 11 scans @ K(1S): ∫L dt = 0.27 fb-1 6 scans @ K(2S): ∫L dt = 0.08 fb-1 7 scans @ K(3S): ∫L dt = 0.22 fb-1 ∫L dt = 0.19 fb-1 ∫L dt = 0.41 fb-1 ∫L dt = 0.14 fb-1 T. Ferguson

  5. Di-electron Widths of K(1S,2S,3S) Resonances Gee measurement method: • Fit the hadronic cross-section and get GeeGhad/Gtot. • Correct for the missing leptonic modes. Use Bmm to get Gee (assuming Bee=Bmm=Btt). Main backgrounds: • Two-photon events (e+e- e+e-X). ~ln s. • Cosmic rays and beam gas interactions. • Background from the high-energy tails of the K(1S) and K(2S). The figure shows the event yields as a function of Ecm in the K(3S) region. Top points are data with the fit superimposed. Dashed curve – the sum of all backgrounds. The lower points and lines show the individual backgrounds. T. Ferguson

  6. Di-electron Widths of K(1S,2S,3S) Resonances • Subtract cosmic ray and beam-gas backgrounds. • Fit each resonance to convolution of: - Breit-Wigner resonance including interference between K qq and e+e-  qq - Initial-state radiation - Gaussian spread in CESR beam energy of (4 MeV) - Background terms proportional to 1/s and ln(s) • Statistical errors: 0.3% (K(1S)), 0.7% (K(2S)), 1.0% (K(3S)). • Main systematic errors: luminosity measurement (1.3%), hadronic efficiency (0.5%). T. Ferguson

  7. Di-electron Widths of K(1S,2S,3S) Resonances PDG % Error % Error Assuming Bee = Bmm gives: Gtot[K(1S)] = 54.4  0.2 (stat.)  0.8 (syst.)  1.6 (sBmm) keV Gtot[K(2S)] = 30.5  0.2 (stat.)  0.5 (syst.)  1.3 (sBmm)keV Gtot[K(3S)] = 18.6  0.2 (stat.)  0.3 (syst.)  0.9 (sBmm)keV T. Ferguson

  8. Di-electron Widths of K(1S,2S,3S) Resonances • Comparison with newest unquenched lattice QCD results, • Most precise parameter = • = 0.48  0.05 - Lattice QCD, A.Gray et al., Phys. Rev. D72, 094507 (2005). • =0.514  0.007 – CLEO, J.L.Rosner et al., Phys. Rev. Lett. 96, 092003 (2006). The final lattice QCD results are expected to have a few percent precision in Gee(nS)/Gee(mS) and ~10% in Gee(nS). T. Ferguson

  9. Measurement of Gee(J/y), Gtot(J/y), Gee[y(2S)]/Gee(J/y) • Use data at y(3770), look for radiative return events to J/y. • Select m+m-(g) events with a M(m+m-) = M(J/y). • Resulting cross-section proportional to Bmmx Gee(J/y). • Divide by new CLEO Bmm (1.2% precision) to get Gee(J/y). • Assume Bee = Bmm,divide by again to get Gtot(J/y). R e s u l t s: B(J/ym+m-) x Gee(J/y) = 0.3384  0.0058 (stat.)  0.0071 (syst.) keV Gee(J/y) = 5.68  0.11 (stat.)  0.13 (syst.)keV Gtot(J/y) = 95.5  2.4 (stat.)  2.4 (syst.)keV T. Ferguson

  10. Measurement of Gee(J/y), Gtot(J/y), Gee[y(2S)]/Gee(J/y) • Using a recent CLEO measurement of Gee[y(2S)], Gee[y(2S)] = 2.54  0.03  0.11 keV,we determine the ratio: Gee[y(2S)]/Gee(J/y) = 0.45  0.01 (stat.)  0.02 (syst.) G.S. Adams et al., Phys. Rev. D73, 051103 (R), (2006). T. Ferguson

  11. Measurement of s(y(3770)hadrons) and Gee(y(3770) • Lead-Glass Wall (1977), Mark II (1981) measured s(y(3770)  hadrons) ~10 nb. • Mark III (1988) using a double-tag technique measured s(y(3770)  DD) ~5 nb. • Complete surprise since s(y(3770)  non-DD)<<s(y(3770)  DD). • CLEO repeats Mark III measurement: s(y(3770)  DD) = (6.39  0.10 +0.17-0.08) nb. Q. He et al., Phys. Rev. Lett. 95, 121801 (2005). • So remeasure s(y(3770)  hadrons) using: Ny(3770) = number of observed hadron events from y(3770) decays. ey(3770)= hadron event efficiency, = 80%. Ly(3770) = integrated luminosity, = (281.3  2.8) pb-1. T. Ferguson

  12. Measurement of s(y(3770)hadrons) and Gee(y(3770) Non-y(3770)is the observed number of hadronic events in the y(3770) data. Nqq– number of the hadronic events from e+e- g*  qq. Ny(2S) / NJ/y &Nl+l-- number of hadronic events from y(2S) / J/y & from e+e-l+l-. sy(3770) = (6.38  0.08 +0.41-0.30) nb D. Besson et al., hep-ex/0512038 Significantly smaller than Lead-Glass Wall and Mark II measurements. sy(3770) – sy(3770)DD= (-0.01  0.08 +0.41-0.30) nb Consistent with only small s(y(3770)  non-DD). Mystery solved. • Using our s(y(3770)  hadron) number and M and Gtot from PDG, get: Gee (y(3770)) = (0.204  0.003 +0.041-0.027) keV • Consistent with PDG value of 0.26  0.04. T. Ferguson

  13. Charmonium decays of y(4040), y(4160) & U(4260) The region at center-of-mass energies above charmonium open-flavor production threshold is of great theoretical interest due to its richness of cc states, the properties of which are not well understood. C. Quigg, J. Rosner, Phys. Lett. B71, 153 (1977) U(4260) V(r) = C ln(r/r0) Main characteristics of states above open-charm threshold: • Large total widths; • Weaker couplings to leptons than the J/y and y(2S); • Decays to closed-charm states are not favored. Prominent structures in the hadronic cross-section are the y(3770), the y(4040) and the y(4160). T. Ferguson

  14. Charmonium decays of y(4040), y(4160) & U(4260) B.Aubert et al., Phys. Rev. Lett. 95, 142001 (2005) Mass: M = 4259  8 +2-6 MeV Width: Gtot = 88  23 +6-4 MeV Coupling: Gee x B(U(4260)  p+p-J/y) = 5.5  1.0 +0.8-0.7 eV JPC of U(4260) is 1-- since it is observed in ISR U(4260) located at a local minimum of the total hadronic cross-section. BaBar finds enhancement in e+e- g(p+p-J/y). Not yet confirmed. BaBar Theory explanations of U(4260) Hybrid charmonium (ccg): suppress D(*)D(*), Ds(*)Ds(*); K+K- ≈ p+p-?; p0J/y? p+p-? DD1 as another possible decay of the U(4260). Tetraquark (cs)(cs): member of nonet along with X(3872) & X(3940). Must decay into DsDs. cCJ ρ0 molecule:no decay into p0p0J/y. cCJ wmolecule:p0p0/p+p- ≈ 0.5;gcCJ, ggJ/y, gp+p-p0J/y. Baryonium molecule:tiny KKJ/y; p0p0/p+p- ≈ 1. y(4S) cc state: interference effects produce dip in open- charm. y(4040)  p+p-J/y. R Ecm 4260 MeV T. Ferguson

  15. Charmonium decays of y(4040), y(4160) & U(4260) • To confirm and clarify U(4260), CLEO performed scan from √s = 3.97 – 4.26 GeV. • Look for decays to 16 final states containing a J/y, y(2S), cCJ or f. Scan regions: • y(4040): ∫L dt = 20.7 pb-1 @ √s = 3.97-4.06 GeV • y(4160): ∫L dt = 26.3 pb-1 @ √s = 4.12-4.20 GeV • U(4260):∫L dt = 13.2 pb-1@ √s = 4.26 GeV Born-level Breit-Wigner line shapes between √s = 3.97 & 4.4 GeV indicating the grouping of scan points. The radiative return (RR) process e+e- g y(2S)  XJ/y results in final states which are identical to some of our signal modes. This is one indication that our efficiencies, luminosities and overall normalizations are understood. T. Ferguson

  16. Charmonium decays of y(4040), y(4160) & U(4260) Data taken @ √s = 4.26 GeV. Solid line histogram from MC simulation. Efficiency corrected. Solid histogram from y(2S)-like MC. T. Ferguson

  17. Charmonium decays of y(4040), y(4160) & U(4260) • We confirm (@ 11s significance) the U(4260) p+p-J/y discovery. • First observation of U(4260) p0p0J/y (5.1s). • First evidence for U(4260) K+K-J/y (3.7s). • We measure the following production cross-sections @ √s = 4.26 GeV: • No compelling evidence is found for any other decays in the three resonance regions. We find: • The observation of the p0p0J/y mode disfavors cCJρ0 molecular model. • The fact that the p0p0J/y rate is about half that of p+p-J/y disagrees with the prediction of the baryonium model. • Observation of the KKJ/y decay is also incompatible with these 2 models. • No enhancement for y(4040)  p+p-J/y. Identification U(4260) = y(4S) less attractive. • The results are compatible with hybrid-charmonium interpretation. s(p+p-J/y) = 58 +12-10 4 pb, s(p0p0J/y) = 23 +12-8  1 pb, s(K+K-J/y) = 9 +9-5 1 pb. T.E. Coan et al., hep-ex/0602034 B(y(4040) p+p-J/y) < 0.4% and B(y(4160) p+p-J/y) < 0.4% T. Ferguson

  18. Summary • Precise measurement of Gee for K(1S, 2S, 3S). Good agreement with unquenched lattice QCD result. • Improved determinations of Gee and Gtot for J/y. • New measurement of s(y(3770)  hadrons) – mystery of a large y(3770)  non-DD cross-section solved. • New measurements of closed-charm decays for the y(4040), y(4160) and U(4260): - Confirm the BaBar discovery of U(4260) p+p-J/y. - First observation of U(4260) p0p0J/y. - First evidence of U(4260) K+K-J/y. • Many CLEO heavy-quarkonium results not covered in this talk – see next slide. T. Ferguson

  19. Other Recent CLEO Heavy-Quarkonium Results “Branching Fractions for y(2S) to J/y Transitions“, PRL 94, 232002 (2005); “Measurement of the Branching Fractions for J/y l+l-“, PRD 71, 111103 (2005); “Observation of Thirteen New Exclusive Multi-Body Hadronic Decays of the y(2S)“, PRL 95, 062001 (2005); “Branching Fraction Measurements of y(2S) Decay to Baryon-Antibaryon Final States“, PRD 72, 051108 (2005); “Observation of the hc(1P1) State of Charmonium“, PRL 95, 102003 (2005), PRD 72, 092004 (2005); “Search for Exclusive Multi-Body Non-DD Decays at the y(3770)“, PRL 96, 032003 (2006); “Measurement of the Direct Photon Momentum Spectrum in K(1S), K(2S), and K(3S) Decays“, hep-ex/0512061; “Radiative Decays of the K(1S) to a Pair of Charged Hadrons“, PRD 73, 032001 (2006); “First Observation of y(3770) gcc1ggJ/y“, hep-ex/0509030; “Decay of the y(3770) to Light Hadrons“, PRD 73, 012002 (2006); “Two-Photon Width of the cc2“, S. Dobbs et al., hep-ex/0510033; “Experimental Study of cb(2P) ppcb(1P)“, PRD 73, 012003 (2006); “Radiative Decays of the K(1S) to gp0p0, ghh and gp0h“, hep-ex/0512003; “Observation of y(3770) ppJ/y and Measurement of Gee[y(2S)]”, hep-ex/0508023; “Measurement of y(2S) Decays to two Pseudoscalar Mesons”, hep-ex/0603020; “Search for the non-DD decay y(3770)  KSKL”, hep-ex/0603026. T. Ferguson

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