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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.

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Presentation on theme: "18-25 March 2006T. Ferguson1 Bottomonium and Charmonium Results from CLEO T. Ferguson Carnegie Mellon University The XLI Rencontres de Moriond QCD and."— Presentation transcript:

1 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

2 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

3 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%

4 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

5 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:

6 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%).

7 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

8 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).

9 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

10 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).

11 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.

12 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.

13 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 )

14 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

15 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.

16 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.

17 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

18 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.

19 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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