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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The XLI Rencontres de Moriond
QCD and High Energy Hadronic Interactions
Carnegie Mellon University
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
Inner Drift Chamber:
B field 1.0 T
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:
CESR scanned center-of-mass energies in the vicinity of the K(1S), K(2S) and K(3S) resonances.
Data below resonances to
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
Gee measurement method:
Use Bmm to get Gee (assuming Bee=Bmm=Btt).
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.
- 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)
hadronic efficiency (0.5%).
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
The final lattice QCD results are expected to have a few percent precision in Gee(nS)/Gee(mS) and
~10% in Gee(nS).
return events to J/y.
M(m+m-) = M(J/y).
to get Gee(J/y).
R e s u l t s:
B(J/ym+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
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).
s(y(3770) hadrons) ~10 nb.
s(y(3770) DD) ~5 nb.
s(y(3770) DD) = (6.39 0.10 +0.17-0.08) nb.
Q. He et al., Phys. Rev. Lett. 95, 121801 (2005).
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.
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.
Gee (y(3770)) = (0.204 0.003 +0.041-0.027) keV
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)
V(r) = C ln(r/r0)
Main characteristics of states above open-charm threshold:
Prominent structures in the hadronic
cross-section are the y(3770), the
y(4040) and the y(4160).
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.
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.
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
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 y(2S)-like MC.
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%
y(3770) non-DD cross-section solved.
- 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.
“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) gcc1ggJ/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.