bottomonium and charmonium results from cleo

18-25 March 2006 T. Ferguson 1

Bottomonium and CharmoniumBottomonium and CharmoniumResults from CLEO Results from CLEO

T. FergusonT. FergusonCarnegie Mellon UniversityCarnegie Mellon University

The XLI Rencontres de MoriondThe XLI Rencontres de Moriond

QCD and High Energy Hadronic InteractionsQCD and High Energy Hadronic Interactions

OutlineOutline The CLEO DetectorThe CLEO Detector eeee of the of the (1S, 2S, 3S) Resonances(1S, 2S, 3S) Resonances Measurement of Measurement of eeee(J/(J/), ), tottot(J/(J/), ), eeee[[(2S)]/(2S)]/eeee(J/(J/)) Measurement ofMeasurement of (((3770) (3770) hadrons) and hadrons) and eeee[[(3770)](3770)] Charmonium Decays of Charmonium Decays of (4040), (4040), (4160) & (4160) & (4260)(4260) SummarySummary


The CLEO/CESR ExperimentThe 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, , and 2-photon physics for almost 30years


The CLEO detectorThe 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

GeVParticle Identification:

RICH detector dE/dx in drift chamber Combined (or K) > 90%


Di-electron Widths of Di-electron Widths of (1S,2S,3S) Resonances(1S,2S,3S) Resonances

Precision of previously measured ee: 2.2% for (1S) 4.2% for (2S) 9.4% for (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 (1S), (2S) and (3S) resonances.

11 scans @ (1S): ∫L dt = 0.27 fb-1 6 scans @ (2S): ∫L dt = 0.08 fb-1 7 scans @ (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 toconstrain backgrounds



Fit the hadronic cross-section and get eehad/tot.

Correct for the missing leptonic modes. Use B to get ee (assuming Bee=B=B).

)31/()/( Btothadeeee

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 (1S) and (2S). The figure shows the event yields as a function of Ecm in the (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:



Subtract cosmic ray and beam-gas backgrounds. Fit each resonance to convolution of: - Breit-Wigner resonance including interference between 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% ((1S)), 0.7% ((2S)), 1.0% ((3S)). Main systematic errors: luminosity measurement (1.3%), hadronic efficiency (0.5%).



eehad/tot(1S) 1.252 0.004 0.019 keV

eehad/tot(2S) 0.581 0.004 0.009 keV

eehad/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 Bee = B gives:

tot[(1S)] = 54.4 0.2 (stat.) 0.8 (syst.) 1.6 (B) keVtot[(2S)] = 30.5 0.2 (stat.) 0.5 (syst.) 1.3 (B) keVtot[(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

% ErrorPDG

% Error



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).

)1()1(

)2()2(2

2

SMS

SMS

ee

ee


Measurement ofMeasurement ofeeee(J/(J/), ), tottot(J/(J/), ), eeee[[S)]/S)]/eeee(J/(J/))

Use data at (3770), look for radiative return events to J/

Select +-() events with a M(+-) = M(J/).

Resulting cross-section proportional to Bx ee(J/).

Divide by new CLEO B (1.2% precision) to get ee(J/).

Assume Bee = 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


Measurement ofMeasurement ofeeee(J/(J/), ), tottot(J/(J/), ), eeee[[S)]/S)]/eeee(J/(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.)

CLEO Previous World Average

Bx 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).


Measurement of Measurement of (((3770)(3770)hadrons) and hadrons) and eeee(((3770)(3770)

)(

N

37703770

37703770 L

)(

)()(

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.


Measurement of Measurement of (((3770)(3770)hadrons) and hadrons) and eeee(((3770)(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.

Non-(3770) is the observed number of hadronic events in the (3770) data. Nqq – number of the hadronic events from e+e- * qq. N(2S) / NJ/ & Nl

+l- - number of hadronic events from (2S) / J/& from e+e-

l+l-.

el llJSqqon NNNNNN,,/)2()()( 37703770

D. Besson et al., hep-ex/0512038

Consistent with only small ((3770) non-DD). Mystery solved.


Charmonium decays of Charmonium decays of (4040), (4040), (4160) & (4160) & (4260)(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/r0)



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

JPC of (4260) is 1-- since it is observed in ISR(4260) located at a local minimum of the total hadronic cross-section.

Ecm

R

4260 MeV4260 MeV

Theory explanations of (4260)Hybrid charmonium (ccg): suppress D(*)D(*), Ds(*)Ds(*);

+- ≈ +-?; 0J/? +-? DD1 as another possible decay of the (4260).

Tetraquark (cs)(cs): member of nonet along with X(3872) & X(3940). Must decay into DsDs.

CJ ρ0 molecule: no decay into 00J/.

CJ molecule: 00/ +- ≈ 0.5; CJ, J/, +-0J/.

Baryonium molecule: tiny J/; 00/ +- ≈ 1. (4S) cc state: interference effects produce dip in open-charm. (4040) +-J/

BaBar



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.



Data taken @ √√s = 4.26 GeV.Solid line histogram from MC

simulation.

Efficiency corrected. Solid histogram from (2S)-like MC.



We confirm (@ 11 significance) the (4260) +-J/discovery. First observation of (4260) 00J/ (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 00J/mode disfavors CJρ0 molecular model. The fact that the 00J/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,

(00J/) = 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


SummarySummary

Precise measurement of ee for (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) 00J/. - First evidence of (4260) +-J/.

Many CLEO heavy-quarkonium results not covered in this talk – see next slide.


Other Recent CLEO Heavy-Quarkonium ResultsOther 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 hc(1P1) 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 (1S), (2S), and (3S) Decays“, hep-ex/0512061;

“Radiative Decays of the (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 (1S) to 00, 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) KSKL”, hep-ex/0603026.

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