Charmonium above (3770)• Study of resonance formation in energy regime

above J/(3770). • CLEO probes direct production of “new states” via

couping to electron-positron collisions• Constrains possible quantum numbers (as does

production in ISR a la’ Belle/BaBar)• Take advantage of recent ‘scan’ to locate peak of Ds

production cross-section in region between 3.9-4.3 GeV c.o.m. and study new charmonia.

• THANKS TO BRIAN HELTSLEY & HANNA MAHLKE-KRUGER, FROM WHOM I SHAMELESSLY LIFTED SLIDES WHOLESALE!

Charmonium, retrospective• J/(3090) observation (1974) ushers in modern

heavy-quark era

• Spectroscopy of states below threshold generally conforms to potential model expectations

• Belle ushers in “new” era looking at mass recoiling against strange-meson states in exclusive B-decays (3872), etc…

• Recent charmonium Renaissance;– CLEO-c well poised to contribute!

(some) recent CLEO-c charmonium papers…

• Measurement of ee(J/), tot(J/), ee[(2S)]/ee(J/)

hep-ex/0512046

• Experimental Study of chib(2P) -> pi pi chib(1P)

Phys.Rev. D73 (2006) 012003

• Two Photon Width of chic2 (submitted to PRL)

• Observation of the 1P1 State of Charmonium Phys.

Rev. Lett.95:102003,2005

• Measurement of Branching Fractions for J/l+ l- Phys.

Rev. D71:111103,2005

• Branching Fractions for psi(2S) to J/psi Transitions Phys. Rev. Lett.94:232002,2005

Comment on J/(3770)DDbarCLEO has now determined (3770)DD/(3770)hadrons

ECM=3671 MeV evt yield (x1000) ECM=3770 MeV evt yield (x1000)

Open charm production nearly saturates (3770)!

J/(3770), cont.• “Almost” saturates – CLEO has published:

– Dipion transitions to (1S) state, submitted PRL

– Radiative transitions to c,1 state, submitted PRL

– But not hadronic charmless modes (30 modes in two analyses) Phys.Rev. D73 (2006) 012002

Pre-CLEO cross-section tabulation (PDG)

Eric Swanson, hep-ph/0601110

How do dipion transitions compete with allowed DD decays?

CLEO study of charmonia > (3770)• Search in dipion (or even dikaon transitions):

– X(J/; for both neutral and charged dipions.– J/decays leptonically, resulting in very clean &

distinctive final state.

• Complications:– Tails of Breit-Wigner resonances lurk everywhere– E.g., some of observed (J/final state at high

energies may be either tail of (2S) or ISR radiation to peak of (2S). Former calculable, latter distinctive by missing energy / momentum-imbalance carried by missing ISR photon (typically down beampipe).

– Advantage: Opportunity to calibrate systematics…

Note: ISR photon not necessarily constructed; distinguishable on basis of missing momentum

Expectation

Y(4260) reconstruction• Data taken directly on peak (13.2/pb), part of a scan

of 3.974.26 GeV center-of-mass range.

• Note: not enough data to measure intrinsic width of putative resonance (88+/-23+/-5 MeV, BaBar) or mass (4259+/-8 MeV, BaBar)

• Tabulate contributions to (J/Jl+l- final state, look for excess beyond contribution expected from (2S) + non-resonant processes

• Cut on missing momentum to exclude ISR (2S) contributions

((2S) ISR off-scale)

Compile observed cross-section as function of c.o.m. energy

Dipion mass distributions look “Yan-like”

Search for 3 states in other modes• Extend search to include many other modes,

including hadronic transitions to (2S), radiative and hadronic transitions to c states, dipion transitions to phi, and other hadronic transitions to J/

• No signals found in any other modes; upper limits set on (BR*cross-section)

So….

1. hep-lat/0512029 [abs, ps, pdf, other] :

Title: Y(4260) on the latticeTWQCD Collaboration: Ting-Wai Chiu, Tung-Han Hsieh 

2. hep-ph/0511107 [abs, ps, pdf, other] :

Title: The Y(4260) as an omega chi_{c1} molecular stateC.Z. Yuan, P. Wang, X.H. Mo

3. hep-ph/0510228 [abs, ps, pdf, other] :

Title: One Explanation for the Exotic State Y(4260)Cong-Feng Qiao (GUCAS)

4. hep-ph/0507177 [abs, ps, pdf, other] :

Title: Possible Molecular Structure of the Newly Observed Y(4260) Authors: Xiang Liu, Xiao-Qiang Zeng, Xue-Qian Li

5. hep-ph/0507119 [abs, ps, pdf, other] :

Title: Suppressed decay into open charm for the Y(4260) being an hybrid Authors: E. Kou, O. Pene

6. hep-ph/0507062 [abs, ps, pdf, other] :

Title: Four Quark Interpretation of Y(4260)Authors: L. Maiani, F. Piccinini, A.D. Polosa, V. Riquer

7. hep-ph/0507025 [abs, ps, pdf, other] :

Title: The Possible Interpretations of Y(4260)Authors: Shi-Lin Zhu

Recent theoretical interest

1. hep-ph/0511005 [abs, ps, pdf, other] :

Title: Quark--antiquark states and their radiative transitions in terms of the spectral integral equation. II. CharmoniaV. Anisovich, L.Dakhno, M.Matveev, V.Nikonov, A.Sarantsev

2. hep-ph/0411291 [abs, ps, pdf, other] :

Title: Leptonic widths of high excitations in heavy quarkoniaAuthors: A.M. Badalian, A.I. Veselov, B.L.G. Bakker

3. hep-ph/0410361 [abs, ps, pdf, other] :

Title: Charmed quark component of the photon wave functionAuthors: V.V. Anisovich, L.G. Dakhno, V.N. Markov, V.A. Nikonov, A.V. Sarantsev

4. hep-ph/9507407 [abs, ps, pdf, other] :

Title: Do psi(4040), psi(4160) signal Hybrid Charmonium?Authors: Frank E. Close, Philip R. Page

And….

Summary• Confirm BaBar e+e-Y(4260)J/

pb

• New observations of e+e-Y(4260)J/ and

e+e-Y(4260)J/ (=23+12-8 pb and 9+9

-5 pb)

• Similar dipion transitions from (4040) or (4160) states not observed.

• Early results favor hybrid charmonium interpretation.

• CLEO III intends now to exhaustively study particle production in this energy regime!