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18-25 March 2006T. Ferguson1 Bottomonium and Charmonium Results from CLEO T. Ferguson Carnegie Mellon University The XLI Rencontres de Moriond QCD and High Energy Hadronic Interactions Outline Outline The CLEO Detector ee of the K (1S, 2S, 3S) Resonances Measurement of ee (J/ ), tot (J/ ), ee [ (2S)]/ ee (J/ ) Measurement of ( (3770) hadrons) and ee [ (3770)] Charmonium Decays of (4040), (4160) & (4260) Summary
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18-25 March 2006 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, and 2-photon physics for almost 30 years
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18-25 March 2006 T. Ferguson 3 The CLEO detector Inner Drift Chamber: 6 stereo layers 100 m hit resolution Drift Chamber: 47 layers 93% of 4 p/p = 0.6% @ p=1.0 GeV CsI Calorimeter: 93% of 4 E/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 ( or K) > 90%
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18-25 March 2006 T. Ferguson 4 Di-electron Widths of K (1S,2S,3S) Resonances Precision of previously measured ee : 2.2% for K (1S) 4.2% for K (2S) 9.4% for K (3S) Di-electron widths ( ee ) are basic parameters of any onium system. Their measurement can also test new unquenched lattice QCD calculations. CESR scanned center-of-mass energies in the vicinity of the K (1S), K (2S) and K (3S) resonances. 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 Data below resonances to constrain backgrounds
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18-25 March 2006 T. Ferguson 5 Di-electron Widths of K (1S,2S,3S) Resonances Fit the hadronic cross-section and get ee had / tot. Correct for the missing leptonic modes. Use B to get ee (assuming B ee = B =B ). 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 E cm 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. ee measurement method:
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18-25 March 2006 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%).
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18-25 March 2006 T. Ferguson 7 Di-electron Widths of K (1S,2S,3S) Resonances ee had / tot (1S)1.252 0.004 0.019 keV ee had / tot (2S)0.581 0.004 0.009 keV ee had / tot (3S)0.413 0.004 0.006 keV ee (1S)1.354 0.004 0.020 keV ee (2S)0.619 0.004 0.010 keV ee (3S)0.446 0.004 0.007 keV ee (2S)/ ee (1S)0.457 0.004 0.004 ee (3S)/ ee (1S)0.329 0.003 0.003 ee (3S)/ ee (2S)0.720 0.009 0.007 Assuming B ee = B gives: tot [ K (1S)] = 54.4 0.2 (stat.) 0.8 (syst.) 1.6 ( B ) keV tot [ K (2S)] = 30.5 0.2 (stat.) 0.5 (syst.) 1.3 ( B ) keV tot [ K (3S)] = 18.6 0.2 (stat.) 0.3 (syst.) 0.9 ( B ) keV 1.5 2.2 1.7 4.2 1.8 9.4 % Error PDG % Error
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18-25 March 2006 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 ee (nS)/ ee (mS) and ~10% in ee (nS).
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18-25 March 2006 T. Ferguson 9 Measurement of ee (J/ ), tot (J/ ), ee [ S)]/ ee (J/ ) Use data at (3770), look for radiative return events to J/ Select + - ( ) events with a M( + - ) = M(J/ ). Resulting cross-section proportional to B x ee (J/ ). Divide by new CLEO B (1.2% precision) to get ee (J/ ). Assume B ee = B , divide by again to get tot (J/ ). R e s u l t s: B( J/ + - ) x ee (J/ ) = 0.3384 0.0058 (stat.) 0.0071 (syst.) keV ee (J/ ) = 5.68 0.11 (stat.) 0.13 (syst.) keV tot (J/ ) = 95.5 2.4 (stat.) 2.4 (syst.) keV
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18-25 March 2006 T. Ferguson 10 Measurement of ee (J/ ), tot (J/ ), ee [ S)]/ ee (J/ ) Using a recent CLEO measurement of ee [ (2S)], ee [ (2S)] = 2.54 0.03 0.11 keV, we determine the ratio: ee [ (2S)]/ ee (J/ ) = 0.45 0.01 (stat.) 0.02 (syst.) CLEOPrevious World Average B x ee 3.0% 3.2% ee 3.0% 3.1% tot 3.4% 3.5% ee (2S)/ ee (1S) 4.9% 6.5% G.S. Adams et al., Phys. Rev. D73, 051103 (R), (2006).
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18-25 March 2006 T. Ferguson 11 Measurement of ( (3770) hadrons) and ee ( (3770) Lead-Glass Wall (1977), Mark II (1981) measured ( (3770) hadrons) ~10 nb. Mark III (1988) using a double-tag technique measured ( (3770) DD) ~5 nb. Complete surprise since ( (3770) non-DD) << ( (3770) DD). CLEO repeats Mark III measurement: ( (3770) DD) = (6.39 0.10 +0.17 -0.08 ) nb. Q. He et al., Phys. Rev. Lett. 95, 121801 (2005). So remeasure ( (3770) hadrons) using: N (3770) = number of observed hadron events from (3770) decays. (3770) = hadron event efficiency, = 80%. L (3770) = integrated luminosity, = (281.3 2.8) pb -1.
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18-25 March 2006 T. Ferguson 12 Measurement of ( (3770) hadrons) and ee ( (3770) (3770) = (6.38 0.08 +0.41 -0.30 ) nb Significantly smaller than Lead-Glass Wall and Mark II measurements. (3770) – (3770) DD = (-0.01 0.08 +0.41 -0.30 ) nb Using our ( (3770) hadron) number and M and tot from PDG, get: ee ( (3770)) = (0.204 0.003 +0.041 -0.027 ) keV Consistent with PDG value of 0.26 0.04. N on- (3770) is the observed number of hadronic events in the (3770) data. N qq – number of the hadronic events from e + e - * qq. N (2S) / N J/ & N l + l - - number of hadronic events from (2S) / J/ & from e + e - l + l -. D. Besson et al., hep-ex/0512038 Consistent with only small ( (3770) non-DD). Mystery solved.
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18-25 March 2006 T. Ferguson 13 Charmonium decays of (4040), (4160) & (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. Prominent structures in the hadronic cross-section are the (3770), the (4040) and the (4160). Main characteristics of states above open-charm threshold: Large total widths; Weaker couplings to leptons than the J/ and (2S); Decays to closed-charm states are not favored. (4260) C. Quigg, J. Rosner, Phys. Lett. B71, 153 (1977) V(r) = C ln(r/r 0 )
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18-25 March 2006 T. Ferguson 14 Charmonium decays of (4040), (4160) & (4260) BaBar finds enhancement in e + e - ( + - J/ . Not yet confirmed. B.Aubert et al., Phys. Rev. Lett. 95, 142001 (2005) Mass: M = 4259 8 +2 -6 MeV Width: tot = 88 23 +6 -4 MeV Coupling: ee x B( (4260) + - J/ = 5.5 1.0 +0.8 -0.7 eV J PC of (4260) is 1 -- since it is observed in ISR (4260) located at a local minimum of the total hadronic cross-section. E cm R 4260 MeV Theory explanations of (4260) Hybrid charmonium (ccg): suppress D(*)D(*), D s (*)D s (*); + - ≈ + - ?; 0 J/ ? + - ? DD 1 as another possible decay of the (4260). Tetraquark (cs)(cs): member of nonet along with X(3872) & X(3940). Must decay into D s D s. CJ 0 molecule: no decay into 0 0 J/ . CJ molecule: 0 0 / + - ≈ 0.5; CJ, J/ , + - 0 J/ . Baryonium molecule: tiny J/ ; 0 0 / + - ≈ 1. (4S) cc state: interference effects produce dip in open- charm. (4040) + - J/ BaBar
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18-25 March 2006 T. Ferguson 15 Charmonium decays of (4040), (4160) & (4260) √ To confirm and clarify (4260), CLEO performed scan from √s = 3.97 – 4.26 GeV. Look for decays to 16 final states containing a J/ , (2S), CJ or Scan regions: √ (4040): ∫ L dt = 20.7 pb -1 @ √s = 3.97-4.06 GeV √ (4160): ∫ L dt = 26.3 pb -1 @ √s = 4.12-4.20 GeV √ (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 - (2S) XJ/ 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.
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18-25 March 2006 T. Ferguson 16 Charmonium decays of (4040), (4160) & (4260) √ Data taken @ √s = 4.26 GeV. Solid line histogram from MC simulation. Efficiency corrected. Solid histogram from (2S)-like MC.
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18-25 March 2006 T. Ferguson 17 Charmonium decays of (4040), (4160) & (4260) We confirm (@ 11 significance) the (4260) + - J/ discovery. First observation of (4260) 0 0 J/ (5.1 ). First evidence for (4260) + - J/ (3.7 ). √ 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 0 0 J/ mode disfavors CJ 0 molecular model. The fact that the 0 0 J/ rate is about half that of + - J/ disagrees with the prediction of the baryonium model. Observation of the J/ decay is also incompatible with these 2 models. No enhancement for (4040) + - J/ Identification (4260) = (4S) less attractive. The results are compatible with hybrid-charmonium interpretation. ( + - J/ ) = 58 +12 -10 4 pb, ( 0 0 J/ ) = 23 +12 -8 1 pb, ( + - J/ ) = 9 +9 -5 1 pb. B( (4040) + - J/ ) < 0.4% and B( (4160) + - J/ ) < 0.4% T.E. Coan et al., hep-ex/0602034
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18-25 March 2006 T. Ferguson 18 Summary Precise measurement of ee for K (1S, 2S, 3S). Good agreement with unquenched lattice QCD result. Improved determinations of ee and tot for J/ . New measurement of ( (3770) hadrons) – mystery of a large (3770) non-DD cross-section solved. New measurements of closed-charm decays for the (4040), (4160) and (4260): - Confirm the BaBar discovery of (4260) - J/ . - First observation of (4260) 0 0 J/ . - First evidence of (4260) + - J/ . Many CLEO heavy-quarkonium results not covered in this talk – see next slide.
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18-25 March 2006 T. Ferguson 19 Other Recent CLEO Heavy-Quarkonium Results Other Recent CLEO Heavy-Quarkonium Results “Branching Fractions for (2S) to J/ Transitions“, PRL 94, 232002 (2005); “Measurement of the Branching Fractions for J/ l + l - “, PRD 71, 111103 (2005); “Observation of Thirteen New Exclusive Multi-Body Hadronic Decays of the (2S)“, PRL 95, 062001 (2005); “Branching Fraction Measurements of (2S) Decay to Baryon-Antibaryon Final States“, PRD 72, 051108 (2005); “Observation of the h c (1P 1 ) State of Charmonium“, PRL 95, 102003 (2005), PRD 72, 092004 (2005); “Search for Exclusive Multi-Body Non-DD Decays at the (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 (3770) c1 J/y“, hep-ex/0509030; “Decay of the (3770) to Light Hadrons“, PRD 73, 012002 (2006); “Two-Photon Width of the c2 “, S. Dobbs et al., hep-ex/0510033; “Experimental Study of b (2P) b (1P)“, PRD 73, 012003 (2006); “Radiative Decays of the K (1S) to 0 0, and 0 “, hep-ex/0512003; “Observation of (3770) J/ and Measurement of ee [ (2S)]”, hep-ex/0508023; “Measurement of (2S) Decays to two Pseudoscalar Mesons”, hep-ex/0603020; “Search for the non-DD decay y(3770) K S K L ”, hep-ex/0603026.
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